@font-face{font-family:"Inter";font-style:normal;font-weight:400 700;font-display:swap;src:url(/fonts/inter.woff2) format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@font-face{font-family:"Plus Jakarta Sans";font-style:normal;font-weight:500 800;font-display:swap;src:url(/fonts/jakarta.woff2) format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@font-face{font-family:"Source Serif 4";font-style:italic;font-weight:600;font-display:swap;src:url(/fonts/serifi.woff2) format("woff2");unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}/* Style B (2026-10-20): warm off-white page, navy ink, gold accent. Plus Jakarta Sans headings, Inter text, a serif italic for the occasional accent. One button system, soft panels with hairline borders. Old token names (--desk, --lamp, --coral ...) are kept and remapped so the part files keep working. */:root{--bg:#ffffff;--desk:#ffffff;--desk-2:#fafafa;--desk-3:#ffffff;--card:#ffffff;--paper:#ffffff;--tint:#f5f5f5;--text:#1b2a4a;--ink:#1b2a4a;--dim:#47536d;--ink-2:#47536d;--mute:#5f697d;--edge:#ebebeb;--line:#ebebeb;--line2:#dcdcdc;--line3:#c4c4c4;--lamp:#8a5a14;--gold:#a9742a;--coral:#a9742a;--coral-ink:#8a5a14;--hl:#f6ecd0;--gold-t:rgba(27,42,74,.06);--gold-t2:rgba(169,116,42,.26);--gold-b:#d3d7e0;--hov:rgba(27,42,74,.05);--navy:#1b2a4a;--navy-2:#24365e;--on-navy:#ffffff;--btn1:#24365e;--btn2:#1b2a4a;--btn1h:#2b4070;--btn2h:#1f3160;--mint:#2f7d4f;--lv-f:#2f7d4f;--lv-c:#2463a6;--lv-e:#c26a12;--lv-x:#b3261e;--s1:#2b3a52;--ok-t:#0b6b4f;--ok-bg:#effaf5;--ok-b:#9fdcc6;--bad-t:#a3301a;--bad-bg:#fff1ec;--bad-b:#f5b4a3;--warn-t:#8a5a00;--warn-bg:#fff8e8;--warn-b:#f0d293;--mint-bg:#eef8f3;--mint-bg2:#e3f4ec;--mint-ink:#21463a;--mint-b:#9fd2bd;--focus:#2463a6;--bd5:#2f7d4f;--bd4:#2463a6;--bd3:#7a52c7;--bd2:#5f697d;--sh1:0 1px 2px rgba(27,42,74,.05),0 4px 12px rgba(27,42,74,.04);--sh2:0 2px 4px rgba(27,42,74,.05),0 12px 28px rgba(27,42,74,.08);--rl:16px;--rs:12px;--head:"Plus Jakarta Sans",Inter,system-ui,-apple-system,"Segoe UI",sans-serif;--body:Inter,system-ui,-apple-system,"Segoe UI",sans-serif;--mono:Inter,system-ui,-apple-system,"Segoe UI",sans-serif;--serif:"Source Serif 4",Georgia,serif;--hand:"Source Serif 4",Georgia,serif;--w:1240px;color-scheme:light}/* dark mode (2026-10-20): the same tokens, redefined. Screen only, so printing and PDFs stay light. */@media screen{:root[data-theme="dark"]{--bg:#0f1420;--desk:#0f1420;--desk-2:#131a28;--desk-3:#161c2a;--card:#161c2a;--paper:#161c2a;--tint:#1d2536;--text:#e8ecf3;--ink:#e8ecf3;--dim:#a7b0c0;--ink-2:#a7b0c0;--mute:#8d97a9;--edge:#263043;--line:#263043;--line2:#34405a;--line3:#44516c;--lamp:#e0b25c;--gold:#e0b25c;--coral:#e0b25c;--coral-ink:#e0b25c;--hl:#3a3220;--gold-t:rgba(224,178,92,.14);--gold-t2:rgba(224,178,92,.28);--gold-b:rgba(224,178,92,.45);--hov:rgba(255,255,255,.06);--navy:#e8ecf3;--navy-2:#f3f5f9;--on-navy:#0f1420;--btn1:#f3f5f9;--btn2:#dfe4ee;--btn1h:#ffffff;--btn2h:#eef1f7;--mint:#4fbf80;--lv-f:#4fbf80;--lv-c:#6aa8ff;--lv-e:#f0a04b;--lv-x:#ff7a6e;--s1:#8fa4cf;--ok-t:#6fd3a1;--ok-bg:#12281f;--ok-b:#2d5c47;--bad-t:#ff9a8c;--bad-bg:#34191a;--bad-b:#6b2f2a;--warn-t:#f0c36a;--warn-bg:#2f2815;--warn-b:#5c4a22;--mint-bg:#12281f;--mint-bg2:#163326;--mint-ink:#bfe8d3;--mint-b:#2d5c47;--focus:#8ab8ff;--bd5:#4fbf80;--bd4:#6aa8ff;--bd3:#b79aff;--bd2:#a7b0c0;--sh1:0 1px 2px rgba(0,0,0,.3),0 4px 12px rgba(0,0,0,.2);--sh2:0 2px 4px rgba(0,0,0,.3),0 12px 28px rgba(0,0,0,.35);color-scheme:dark}}*{box-sizing:border-box}[hidden]{display:none!important}html{-webkit-text-size-adjust:100%}body{margin:0;background:var(--desk);color:var(--text);font:400 16px/1.6 var(--body);overflow-x:hidden;-webkit-font-smoothing:antialiased}img{max-width:100%;height:auto;display:block}a{color:var(--lamp);text-underline-offset:3px}a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible,select:focus-visible{outline:2px solid var(--focus);outline-offset:3px;border-radius:8px}h1,h2,h3{font-family:var(--head);letter-spacing:-.03em;line-height:1.1;margin:0 0 .45em;text-wrap:balance;font-weight:800;color:var(--text)}h1{font-size:clamp(38px,5.4vw,70px)}h2{font-size:clamp(28px,3.8vw,46px)}h3{font-size:19px;letter-spacing:-.02em;line-height:1.25}p{margin:0 0 1em}.wrap{max-width:var(--w);margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}.skip{position:absolute;left:-999px}.skip:focus{left:16px;top:8px;background:#fff;color:#1b2a4a;padding:8px;z-index:99}/* paper: light cards that sit on the desk */.card,.paper,.book-card,.steps li,.offer,details,.ptable,.thumbs a{background:var(--paper);color:var(--ink);border:1px solid var(--line);box-shadow:var(--sh1)}.card a:not(.btn),.paper a:not(.btn),.book-card a,.steps li a,.offer a:not(.btn),details a,.ptable a{color:var(--coral-ink)}/* header */header.site{position:sticky;top:env(safe-area-inset-top,0px);z-index:40;background:color-mix(in srgb,var(--bg) 92%,transparent);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}header.site .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;height:66px}.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);font:800 19px var(--head);letter-spacing:-.02em}.logo svg{width:34px;height:34px;flex:none}.logo em{font-style:normal;font-weight:600;color:var(--dim)}:root{--owl-ink:#1b2a4a;--owl-ink2:#102843}@media screen{:root[data-theme="dark"]{--owl-ink:#e8ecf3;--owl-ink2:#c3cad6}}.logo i{font-style:italic;font-family:var(--serif);font-weight:600;color:var(--gold)}nav.main ul{list-style:none;margin:0;padding:0;display:flex;gap:2px}nav.main a{display:block;text-decoration:none;color:var(--dim);font-weight:500;font-size:14.5px;padding:8px 11px;border-radius:8px}nav.main a:hover{color:var(--text);background:var(--hov)}nav.main a[aria-current]{background:var(--gold-t);color:var(--lamp)}.signin{display:inline-flex;align-items:center;justify-content:center;gap:6px;height:44px;background:linear-gradient(var(--btn1),var(--btn2));color:var(--on-navy);text-decoration:none;font-weight:600;font-size:14.5px;padding:0 18px;border-radius:10px;white-space:nowrap;box-shadow:inset 0 1px 0 rgba(255,255,255,.18),0 1px 2px rgba(27,42,74,.3),0 6px 14px rgba(27,42,74,.16)}.signin:hover{background:linear-gradient(var(--btn1h),var(--btn2h))}@media(max-width:900px){nav.main{display:none}}/* breadcrumbs + page hero */.crumbs{font:500 13px var(--body);padding-top:18px}.crumbs ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:6px;color:var(--dim)}.crumbs li+li:before{content:"/";margin-right:6px;opacity:.5}.crumbs a{color:var(--dim);text-decoration:none}.crumbs a:hover{color:var(--text);text-decoration:underline}.hero{position:relative;isolation:isolate;padding-block:30px 64px;overflow-x:clip}.hero:before{content:none}.eyebrow{font:600 12px var(--body);color:var(--lamp);text-transform:uppercase;letter-spacing:.16em;margin:0 0 14px}.card .eyebrow,.paper .eyebrow{color:var(--coral-ink)}.lede{font-size:clamp(17px,1.8vw,19px);color:var(--dim);max-width:58ch;line-height:1.55}.glow,mark{background:linear-gradient(transparent 62%,var(--gold-t2) 62%);color:inherit;padding-inline:.06em}.hand{font:italic 600 22px var(--hand);color:var(--lamp);display:inline-block;margin:0 0 6px}.hero-grid{display:grid;gap:40px;align-items:center}@media(min-width:880px){.hero-grid.book{grid-template-columns:320px 1fr}}.cover{border-radius:3px 8px 8px 3px;box-shadow:0 2px 4px rgba(27,42,74,.12),0 18px 34px -14px rgba(27,42,74,.35);background:var(--line)}.stage{display:flex;justify-content:center;perspective:1200px}.stage.single .cover{max-width:250px;transform:rotateY(-10deg) rotate(-2deg);transition:transform .5s cubic-bezier(.2,.8,.2,1)}.stage.single:hover .cover{transform:rotateY(-2deg)}.fan{display:grid;grid-template-columns:1fr 1fr;max-width:340px;margin:0 auto;perspective:1200px}.fan img:first-child{transform:rotateY(14deg) translateX(10%) rotate(-3deg)}.fan img:last-child{transform:rotateY(-14deg) translateX(-10%) translateY(8%) rotate(3deg)}.pills{list-style:none;margin:0 0 22px;padding:0;display:flex;flex-wrap:wrap;gap:8px}.pills li{font:600 12.5px var(--body);border:1px solid var(--line2);background:var(--card);border-radius:999px;padding:4px 11px;color:var(--ink-2)}.ctas{display:flex;flex-wrap:wrap;gap:12px;margin:6px 0 14px;align-items:center}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;font:600 14.5px/1 var(--body);text-decoration:none;height:44px;padding:0 20px;border-radius:10px;border:0;cursor:pointer;background:var(--card);color:var(--ink);box-shadow:0 0 0 1px var(--line2),0 1px 2px rgba(27,42,74,.06);transition:transform .15s,box-shadow .15s,background .15s;min-height:44px;white-space:nowrap}.btn:hover{transform:translateY(-1px);box-shadow:0 0 0 1px var(--line3),0 6px 14px rgba(27,42,74,.09)}.btn:active{transform:translateY(0)}.btn.primary,.btn.dark{background:linear-gradient(var(--btn1),var(--btn2));color:var(--on-navy);box-shadow:inset 0 1px 0 rgba(255,255,255,.18),0 1px 2px rgba(27,42,74,.3),0 6px 14px rgba(27,42,74,.16)}.btn.primary:hover,.btn.dark:hover{background:linear-gradient(var(--btn1h),var(--btn2h));box-shadow:inset 0 1px 0 rgba(255,255,255,.2),0 2px 4px rgba(27,42,74,.3),0 10px 20px rgba(27,42,74,.2)}.btn.ghost{background:var(--card);color:var(--ink)}.btn[aria-disabled]{opacity:.55;cursor:default;transform:none}.btn:disabled{opacity:.6;cursor:default;transform:none}.btn .arr{transition:transform .2s}.btn:hover .arr{transform:translateX(3px)}.scribble{font:italic 600 20px var(--hand);color:var(--lamp);text-decoration:none;display:inline-block}.note{font-size:14px;color:var(--dim)}.card .note,.paper .note,.offer .note{color:var(--ink-2)}.note a{color:var(--lamp)}.subnav{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 22px}.subnav a{font:600 14px var(--body);text-decoration:none;color:var(--dim);border:1px solid var(--line2);background:var(--card);border-radius:999px;padding:7px 14px}.subnav a:hover{color:var(--text);border-color:var(--line3)}.subnav a[aria-current]{background:var(--navy);border-color:var(--navy);color:var(--on-navy)}.prose .pills{margin-top:6px}/* sections */section.section,section.alt,.sec{padding-block:76px}section.alt{background:color-mix(in srgb,var(--tint) 70%,transparent);border-block:1px solid var(--line)}@media(max-width:700px){section.section,section.alt,.sec{padding-block:54px}}.head{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:end;gap:12px 30px;margin-bottom:32px}.head h2{margin:0}.head p{margin:0;color:var(--dim);max-width:46ch}.grid{display:grid;gap:18px}@media(min-width:760px){.grid.c2{grid-template-columns:1fr 1fr}.grid.c3{grid-template-columns:repeat(3,1fr)}}.card{border-radius:var(--rs);padding:26px 24px;min-width:0}.card p:last-child{margin-bottom:0}.panel{background:var(--card);border:1px solid var(--line);box-shadow:var(--sh1);border-radius:var(--rl);padding:clamp(22px,3vw,30px);min-width:0;color:var(--text)}.panel p{color:var(--dim)}.panel a:not(.btn){color:var(--lamp)}ul.ticks{list-style:none;padding:0;margin:0}ul.ticks li{position:relative;padding-left:26px;margin-bottom:.65em}ul.ticks li:before{content:"";position:absolute;left:2px;top:.6em;width:10px;height:10px;border-radius:50%;background:var(--coral)}/* book cards */.bento{display:grid;gap:22px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}.book-card{position:relative;display:flex;flex-direction:column;gap:12px;border-radius:16px;padding:16px;box-shadow:var(--sh1);transition:transform .3s}.book-card:hover{transform:translateY(-3px);box-shadow:var(--sh2)}.book-card .shelf{background:var(--tint);border-radius:12px;padding:20px 0;display:flex;justify-content:center}.book-card .shelf img{width:42%;max-width:140px;border-radius:3px 6px 6px 3px;box-shadow:var(--sh1)}.book-card .tag{font:500 11.5px var(--mono);text-transform:uppercase;letter-spacing:.06em;color:var(--coral-ink)}.book-card h2,.book-card h3{font-size:20px;margin:0}.book-card h2 a,.book-card h3 a{color:var(--ink);text-decoration:none}.book-card h2 a:after,.book-card h3 a:after{content:"";position:absolute;inset:0;z-index:1}.book-card p{margin:0;color:var(--ink-2);font-size:15px}.book-card .meta{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-top:auto;font-size:14px}.book-card .meta a{position:relative;z-index:2;font-weight:700}.price{font:700 16px var(--head);color:var(--ink);letter-spacing:-.02em}/* steps */.steps{counter-reset:s;list-style:none;padding:0;margin:0;display:grid;gap:16px}@media(min-width:720px){.steps{grid-template-columns:1fr 1fr}}@media(min-width:1040px){.steps.four{grid-template-columns:repeat(4,1fr)}}.steps li{counter-increment:s;border-radius:12px;padding:22px;color:var(--ink-2);font-size:15.5px;box-shadow:var(--sh1)}.steps li:before{content:counter(s,decimal-leading-zero);display:block;font:500 12.5px var(--mono);color:var(--coral-ink);margin-bottom:20px}.steps b{display:block;font:700 18px/1.25 var(--head);letter-spacing:-.02em;color:var(--ink);margin-bottom:6px}/* contents */.vol-h{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:baseline;margin:6px 0 4px}.vol-h h3{margin:0}.vol-h span{font:500 12.5px var(--mono);color:var(--dim)}.toc{list-style:none;padding:0;margin:0 0 26px;display:grid;gap:0 32px}@media(min-width:720px){.toc{grid-template-columns:1fr 1fr}}.toc li{display:flex;gap:14px;padding:11px 0;border-bottom:1px solid var(--edge)}.toc .n{font:500 13px var(--mono);color:var(--lamp);min-width:2.6em;padding-top:2px}/* sample pages */.thumbs{display:grid;gap:16px;grid-template-columns:repeat(2,1fr)}@media(min-width:880px){.thumbs{grid-template-columns:repeat(4,1fr)}}.thumbs figure{margin:0}.thumbs a{display:block;border-radius:10px;overflow:hidden;box-shadow:var(--sh1);transition:transform .3s}.thumbs a:hover{transform:translateY(-3px);box-shadow:var(--sh2)}.thumbs figcaption{font-size:13.5px;color:var(--dim);margin-top:8px;line-height:1.45}/* buy */.offer{display:flex;flex-direction:column;border-radius:16px;padding:24px;box-shadow:var(--sh1)}.offer .btn{margin-top:auto;width:100%}.offer dl{margin:0 0 20px;font-size:15px;display:grid;grid-template-columns:auto 1fr;gap:6px 14px}.offer dt{font:500 11.5px var(--mono);text-transform:uppercase;letter-spacing:.06em;color:var(--ink-2);padding-top:3px}.offer dd{margin:0}.offer .eyebrow{color:var(--coral-ink)}.big{font:800 42px/1 var(--head);letter-spacing:-.045em;margin:2px 0 14px}.big small{font:500 13px var(--body);letter-spacing:0;color:var(--ink-2);margin-left:6px}/* faq */details{border-radius:14px;padding:16px 20px;margin-bottom:10px}summary{cursor:pointer;font:600 16.5px var(--head);letter-spacing:-.02em;list-style:none;display:flex;justify-content:space-between;gap:14px;color:var(--ink)}summary::-webkit-details-marker{display:none}summary:after{content:"+";color:var(--coral-ink);font-size:22px;line-height:1}details[open] summary:after{content:"\2212"}details p{margin:10px 0 0;color:var(--ink-2)}.prose{max-width:72ch}.prose h2{margin-top:1.4em;font-size:clamp(24px,3vw,32px)}.prose h2:first-child{margin-top:0}.prose li{margin-bottom:.5em}.prose p,.prose li{color:var(--dim)}.prose .steps li,.prose .card li,.prose .card p{color:var(--ink-2)}.prose .ptable td:not(:first-child),.prose .ptable th:not(:first-child){text-align:left}.prose .ptable td:nth-child(2),.prose .ptable th:nth-child(2){text-align:center}code{font-family:var(--mono);font-size:.9em;background:var(--desk-3);color:var(--lamp);padding:1px 6px;border-radius:6px}.chip{display:inline-block;font:500 12.5px var(--mono);border:1px solid rgba(169,116,42,.5);color:var(--lamp);border-radius:999px;padding:4px 10px;margin:0 8px 6px 0}.chip.soon{border-color:var(--line2);color:var(--dim)}/* pricing table */.ptable{overflow-x:auto;border-radius:20px;box-shadow:var(--sh1)}.ptable table{width:100%;border-collapse:collapse;min-width:620px}.ptable th,.ptable td{padding:14px 18px;text-align:left;border-bottom:1px solid var(--line);font-size:15px}.ptable thead th{font:700 17px var(--head);vertical-align:bottom}.ptable thead th small{display:block;font:500 13px var(--body);color:var(--ink-2);margin-top:4px}.ptable thead th.pass{background:var(--ink);color:var(--on-navy);border-radius:16px 16px 0 0}.ptable thead th.pass small{color:#cdd0d6}.ptable td.pass{background:var(--tint)}.ptable td:not(:first-child),.ptable th:not(:first-child){text-align:center}.ptable .y{color:var(--mint);font-weight:700}.ptable .no{color:#8b9099}.ptable tbody tr:last-child td{border-bottom:0}.ptable .pr{font:800 24px var(--head);letter-spacing:-.04em}.ptable .lbl{font:500 13px var(--body);color:var(--ink-2)}@media(max-width:700px){.ptable table{min-width:0}.ptable th,.ptable td{padding:10px 6px;font-size:13px}.ptable td:first-child{width:38%}.ptable thead th{font-size:14px}.ptable thead th small{font-size:11px}.ptable .pr{font-size:17px}}/* trust */.trust{display:grid;gap:22px;align-items:start}@media(min-width:900px){.trust{grid-template-columns:1.2fr .8fr}}.author{background:var(--desk-2);border:1px solid var(--edge);border-radius:20px;padding:26px;display:grid;grid-template-columns:auto 1fr;gap:18px}.avatar{width:72px;height:72px;border-radius:50%;background:var(--gold-t);display:grid;place-items:center;font:800 24px var(--head);color:var(--lamp)}.author h3{font-size:21px;margin-bottom:6px}.author p{color:var(--dim);margin:0}.author a{color:var(--lamp)}.author ul{margin:10px 0 0;padding-left:18px;color:var(--dim);font-size:15px;display:grid;gap:4px}.promise{position:relative;background:var(--hl);color:var(--ink);padding:28px 24px 24px;transform:rotate(1.5deg);box-shadow:var(--sh1)}.promise:before{content:"";position:absolute;top:-11px;left:50%;width:76px;height:22px;margin-left:-38px;background:rgba(255,255,255,.5);transform:rotate(-3deg)}.promise h3{font:700 30px var(--hand);letter-spacing:0;margin-bottom:8px}.promise ol{margin:0;padding-left:20px;display:grid;gap:8px;font-size:15px}.faq{max-width:820px}/* footer */footer.site{border-top:1px solid var(--edge);background:color-mix(in srgb,var(--desk-2) 85%,transparent);color:var(--dim);padding-block:52px 40px;font-size:14.5px}footer.site a{color:var(--text);text-decoration:none}footer.site a:hover{color:var(--lamp)}footer.site .cols{display:grid;gap:26px}@media(min-width:800px){footer.site .cols{grid-template-columns:1.4fr repeat(3,1fr)}}footer.site .fh{display:block;font:500 12px var(--mono);text-transform:uppercase;letter-spacing:.1em;color:var(--lamp);margin:0 0 10px;list-style:none;cursor:default}footer.site details.fcol{background:none;border:0;box-shadow:none;border-radius:0;padding:0;margin:0;color:inherit}footer.site .fh{font-size:12px;letter-spacing:.1em;gap:0}footer.site .fh::after{content:none}footer.site .fh::-webkit-details-marker{display:none}@media(max-width:720px){footer.site .cols{gap:0}footer.site .cols>div:first-child{padding-bottom:18px}footer.site details.fcol{border-top:1px solid var(--edge)}footer.site details.fcol>ul{padding-bottom:14px}footer.site .fh{cursor:pointer;margin:0;padding:14px 0;display:flex;justify-content:space-between;align-items:center;min-height:44px}footer.site .fh::after{content:"";display:block;width:8px;height:8px;border-right:2px solid currentColor;border-bottom:2px solid currentColor;transform:rotate(45deg);transition:transform .2s;margin-right:4px}footer.site details[open]>.fh::after{content:"";transform:rotate(-135deg)}}footer.site ul{list-style:none;margin:0;padding:0;display:grid;gap:7px}footer.site .logo{margin-bottom:12px}footer.site p a{text-decoration:underline;text-decoration-color:var(--gold-b)}.disclaimer{border-top:1px solid var(--edge);margin-top:34px;padding-top:20px;font-size:12.5px;color:#8f99a8;line-height:1.65}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}.pane.shot{padding:0}.pane.shot img{width:100%;height:100%;object-fit:cover;object-position:left top;display:block}.pane.shot .lab{position:absolute;left:.9em;bottom:.9em;background:var(--paper);padding:.35em .7em;border-radius:999px;box-shadow:0 4px 14px rgba(0,0,0,.25)}/* consistent rhythm: the first section after a page hero starts closer to it */.hero+section.section,.hero+section.alt{padding-top:28px}.hero+section.alt{padding-top:44px}/* style B: header spacing */header.site .wrap{gap:14px}.logo{flex:none}nav.main>ul>li>a,nav.main summary{border-radius:8px}/* theme toggle */.tgl{display:inline-grid;place-items:center;width:44px;height:44px;border-radius:10px;border:0;background:var(--card);color:var(--ink);cursor:pointer;box-shadow:0 0 0 1px var(--line2),0 1px 2px rgba(27,42,74,.06);padding:0;flex:none}.tgl:hover{box-shadow:0 0 0 1px var(--line3),var(--sh1)}.tgl .ic-moon{display:none}:root[data-theme="dark"] .tgl .ic-sun{display:none}:root[data-theme="dark"] .tgl .ic-moon{display:block}.tgl.wide{display:flex;width:100%;justify-content:center;align-items:center;gap:10px;margin-top:14px;font:600 15px var(--body)}.tgl.wide .ic-sun,.tgl.wide .ic-moon{flex:none}@media(max-width:1000px){header.site .hright>.tgl{display:none}}/* home mock screens always stay light, whatever the theme */.screen,.pad,.mock-light{--ink:#1b2a4a;--text:#1b2a4a;--ink-2:#47536d;--dim:#47536d;--line:#ebebeb;--card:#fff;--paper:#fff;--tint:#f5f5f5;--bg:#fff}.cs-article .diagram,.cs-article .cheatsheet-diagram-wrap,.pq-sheet{--ink:#1b2a4a;--text:#1b2a4a;--ink-2:#47536d;--dim:#47536d;--line:#ebebeb;--card:#fff;--tint:#f5f5f5;color:#1b2a4a}/* dark: line art and screenshots that assume a light page sit on a light panel */@media screen{:root[data-theme="dark"] .pq-fig,:root[data-theme="dark"] .pq-q img,:root[data-theme="dark"] .pq-step img,:root[data-theme="dark"] .cs-article img,:root[data-theme="dark"] .cs-article svg.cs-raster,:root[data-theme="dark"] .db-article img{background:#fff;border-radius:8px;padding:6px}:root[data-theme="dark"] img[src*="/img/books/"],:root[data-theme="dark"] .book-card .shelf img{background:none;padding:0}:root[data-theme="dark"] .btn.g,:root[data-theme="dark"] .btn.ghost{background:var(--card)}:root[data-theme="dark"] body{background:var(--bg)}}/* lean sweep: e-book shelf, samples, pricing, book page (2026-10-22) */.badge-soon{display:inline-block;margin-left:8px;font:600 11px var(--mono);letter-spacing:.06em;text-transform:uppercase;border:1px solid var(--line3);border-radius:999px;padding:3px 10px;color:var(--ink-2);background:var(--card);vertical-align:middle}.bkwrap{display:grid;gap:40px 36px}@media(min-width:1000px){.bkwrap{grid-template-columns:1fr 1fr}}.bkwrap .bgrid{grid-template-columns:repeat(auto-fill,minmax(min(100%,240px),1fr))}.bkgrp>h2{font-size:clamp(22px,2.6vw,28px);margin:0 0 18px}.book-card.bkx .shelf{background:none;padding:6px 0 0}.book-card.bkx .shelf img{width:46%;max-width:170px}.book-card.bkx .shelf.two img{width:40%;max-width:150px}.book-card.bkx .btn.primary{color:var(--on-navy)}.book-card.bkx .btn.ghost{color:var(--ink)}.book-card.bkx .buys .btn.ghost{flex:0 0 auto}.book-card.bkx .meta{flex-wrap:wrap}.book-card.bkx .meta .btn{height:40px;position:relative;z-index:2}.byline{margin:-4px 0 14px;color:var(--dim);font-size:14.5px}.byline a{color:var(--ink);text-decoration-color:var(--gold-b)}.slider{position:relative}.slider .thumbs{display:flex;gap:16px;overflow-x:auto;scroll-snap-type:x mandatory;scrollbar-width:none;padding:4px 2px 8px;-webkit-overflow-scrolling:touch}.slider .thumbs::-webkit-scrollbar{display:none}.slider .thumbs figure{flex:0 0 62%;scroll-snap-align:start}@media(min-width:620px){.slider .thumbs figure{flex-basis:calc(33.33% - 11px)}}@media(min-width:960px){.slider .thumbs figure{flex-basis:calc(25% - 12px)}}.sl-btn{display:none;position:absolute;top:38%;z-index:3;width:44px;height:44px;border-radius:50%;border:1px solid var(--line3);background:var(--card);color:var(--ink);font:400 28px/1 var(--head);cursor:pointer;box-shadow:var(--sh1);align-items:center;justify-content:center;padding:0 0 4px}.sl-btn.prev{left:-14px}.sl-btn.next{right:-14px}.sl-btn:disabled{opacity:.35;cursor:default}@media(min-width:760px){.sl-btn{display:inline-flex}}.otable table{min-width:0}.otable th[scope=row]{font:700 16px var(--head)}.otable td small{color:var(--ink-2);display:block;font-size:12px}.otable td.bt{text-align:right}.otable .btn{white-space:nowrap}.ptable .otable td:not(:first-child){text-align:left}@media(max-width:700px){.otable thead{display:none}.otable table,.otable tbody,.otable tr,.otable td,.otable th{display:block;width:auto}.otable tr{padding:14px 4px;border-bottom:1px solid var(--line)}.otable tr:last-child{border-bottom:0}.otable th,.otable td{border:0;padding:3px 10px;font-size:14px;text-align:left!important}.otable td[data-l]:before{content:attr(data-l)": ";font:500 11px var(--mono);text-transform:uppercase;letter-spacing:.05em;color:var(--ink-2)}.otable td.bt{padding-top:10px}.otable .btn{width:100%}}.ptable thead th.lib{background:var(--ink);color:var(--on-navy);border-radius:16px 16px 0 0}.ptable thead th.lib small{color:#cdd0d6}.ptable td.lib{background:var(--tint)}.ptable .soonc{opacity:.6}.ptable thead th.pass{background:none;color:inherit;border-radius:0}.ptable thead th.soonc small{color:var(--ink-2)}.ptable tfoot td{padding:16px 10px;border:0;text-align:center}.ptable tfoot .btn{height:40px;padding:0 14px;font-size:14px}@media(max-width:700px){.ptable{overflow-x:auto}.ptable table{min-width:560px}.ptable th,.ptable td{padding:10px 6px}.ptable tfoot .btn{padding:0 8px;font-size:12.5px}}/* accounts: /sign-in/, /auth-callback/, /library/ */.ac-hero{padding-bottom:16px}.ac-hero h1{font-size:clamp(34px,4.6vw,56px)}section.ac-sec{padding-top:24px}.ac-box{max-width:520px}.ac-box h2{font-size:clamp(24px,2.6vw,30px)}.ac-box .btn{width:100%}.ac-google{gap:12px}.ac-google svg{background:var(--card);border-radius:50%;padding:2px;width:22px;height:22px}.ac-or{display:flex;align-items:center;gap:12px;margin:22px 0 16px;font:500 12.5px var(--mono);color:var(--ink-2);text-transform:uppercase;letter-spacing:.06em}.ac-or:before,.ac-or:after{content:"";flex:1;height:1px;background:var(--line)}.ac-field{display:grid;gap:6px;margin-bottom:12px;font-size:14px;font-weight:600;color:var(--ink)}.ac-field input{font:500 17px var(--body);color:var(--ink);background:var(--card);border:1.5px solid var(--line2);border-radius:12px;padding:12px 14px;min-height:48px;width:100%}.ac-field input:focus-visible{outline:2px solid var(--coral);outline-offset:2px;border-color:var(--ink)}#acNum{font:700 24px var(--mono);letter-spacing:.3em}.ac-msg{background:var(--bad-bg);color:var(--bad-t);border-radius:10px;padding:10px 14px;font-size:15px;margin:14px 0 0}.section .ac-msg{max-width:720px;margin:0 0 18px}.ac-link{background:none;border:0;padding:0;font:inherit;color:var(--coral-ink);text-decoration:underline;text-underline-offset:3px;cursor:pointer}.ac-legal{max-width:520px;margin-top:16px}.ac-who{display:flex;flex-wrap:wrap;gap:8px 18px;align-items:center;color:var(--dim)}.ac-who[hidden]{display:none}.ac-who b{color:var(--text)}.ac-who .ac-link{color:var(--lamp)}.ac-vols{display:grid;gap:14px;grid-template-columns:repeat(auto-fill,minmax(min(100%,340px),1fr))}.ac-vol{display:grid;grid-template-columns:96px minmax(0,1fr);gap:16px;background:var(--desk-3);border:1px solid var(--edge);border-radius:18px;padding:16px;min-width:0}.ac-vol.own{border-color:var(--gold-b)}.ac-vol h3{margin:0 0 2px;font-size:18px}.ac-vol h3 a{color:var(--text);text-decoration:none}.ac-vol h3 a:hover{text-decoration:underline}.ac-cv img{border-radius:4px 8px 8px 4px;box-shadow:var(--sh1)}.ac-lab{margin:0;font-size:14px;color:var(--dim)}.ac-st{margin:10px 0 4px}.ac-chip{display:inline-block;font:500 12.5px var(--mono);border:1px solid var(--line2);border-radius:999px;padding:3px 10px;color:var(--dim)}.ac-vol.own .ac-chip{border-color:var(--lamp);color:var(--lamp)}.ac-vol.warn .ac-chip{border-color:var(--coral);color:var(--bad-t)}.ac-meta{margin:0 0 10px;font-size:14px;color:var(--dim)}.ac-meta:empty{display:none}.ac-act{margin:0}.ac-act .btn{min-height:42px;padding:9px 16px;font-size:15px}/* My library: PDF library courses, owned first */.ac-courses{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(min(100%,260px),1fr))}.ac-course{display:grid;gap:8px;align-content:start;background:var(--desk-3);border:1px solid var(--edge);border-radius:16px;padding:16px;min-width:0}.ac-course h3{margin:0;font-size:17px}.ac-course.own{border-color:var(--gold-b)}.ac-course.own .ac-chip{border-color:var(--lamp);color:var(--lamp)}.ac-course.warn .ac-chip{border-color:var(--coral);color:var(--bad-t)}.ac-cmeta{margin:0;color:var(--dim);font-size:13.5px}.ac-course .ac-st{display:grid;gap:6px;margin:0;justify-items:start}.ac-cnote{color:var(--dim);font-size:13.5px}.ac-course .ac-act{display:flex;flex-wrap:wrap;gap:8px;margin:0}.ac-course .btn{padding:8px 14px;font-size:14px}.ac-sum{background:var(--desk-2);border:1px solid var(--edge);border-left:4px solid var(--lamp);border-radius:12px;padding:12px 16px;color:var(--text);margin:0 0 14px}.ac-vol .ac-act{display:flex;flex-wrap:wrap;gap:8px}/* My library (lean sweep): jump links, e-book cover shelf, subject rows with HL | SL, Coach card, tool chips */.ac-jump{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}.ac-jump a,.ac-chips a{font:600 14px var(--body);color:var(--ink);text-decoration:none;border:1px solid var(--line2);border-radius:999px;padding:7px 14px;background:var(--card)}.ac-jump a:hover,.ac-chips a:hover{border-color:var(--frame);background:var(--tint)}.ac-chips{display:flex;flex-wrap:wrap;gap:10px;margin:0}.ac-vh{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}.ac-vols{display:flex;gap:14px;overflow-x:auto;scroll-snap-type:x proximity;padding:4px 2px 14px;scrollbar-width:thin}.ac-vol{flex:0 0 min(86%,310px);scroll-snap-align:start;grid-template-columns:84px minmax(0,1fr);gap:14px;padding:14px;border-top:3px solid var(--frame)}.ac-vol h3{font-size:16px;line-height:1.25}.ac-vol .ac-st:empty{display:none}.ac-courses{display:grid;gap:10px;grid-template-columns:1fr;max-width:none}.ac-subj{display:grid;grid-template-columns:170px 1fr 1fr;align-items:stretch;background:var(--card);border:1px solid var(--line);border-left:4px solid var(--frame);border-radius:var(--rs);box-shadow:var(--sh1)}.ac-sn{margin:0;padding:16px 18px;font:800 19px var(--head);align-self:center;color:var(--ink)}.ac-subj .ac-course{border:0;border-left:1px solid var(--line);border-radius:0;box-shadow:none;background:transparent;padding:14px 18px;gap:6px}.ac-subj .ac-course.own{background:color-mix(in srgb,var(--gold) 8%,transparent)}.ac-subj .ac-course h3{font:800 16px var(--head)}.ac-subj .ac-cnote{display:none}.ac-subj .ac-course .ac-st{display:flex}.ac-coach{display:flex;gap:20px 40px;align-items:center;justify-content:space-between;flex-wrap:wrap;background:var(--frame);color:var(--frame-ink);border-radius:var(--rl);padding:26px 32px;border-bottom:3px solid var(--gold)}.ac-coach h2{margin:4px 0;font-size:clamp(22px,2.4vw,28px);color:var(--frame-ink)!important}.ac-coach p{margin:0}.ac-coach .eyebrow{color:#f2d38b}.ac-coach .ac-act{display:flex;gap:10px;flex-wrap:wrap}.ac-coach .btn.primary{background:#fff;color:#1b2a4a;border-color:#fff}.ac-coach .btn.ghost{background:transparent;color:inherit;border-color:rgba(255,255,255,.5)}@media(max-width:760px){.ac-subj{grid-template-columns:1fr 1fr}.ac-sn{grid-column:1/-1;padding:14px 16px 2px}.ac-subj .ac-course{border-left:0;padding:8px 16px 14px}.ac-subj .ac-course+.ac-course{border-left:1px solid var(--line)}.ac-subj .ac-act{flex-direction:column;align-items:stretch}.ac-subj .ac-act .btn{text-align:center}.ac-coach{padding:22px 20px}}/* /admin/ (owner only). Reuses account.css (ac-*) and library.css (pl-tabs). */.op-load{color:var(--dim)}.op-total{font:800 clamp(34px,5vw,54px) var(--head);letter-spacing:-.03em;margin:0 0 4px}.op-sub{color:var(--dim);margin:0 0 18px}.op-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:12px}.op-tbl{width:100%;border-collapse:collapse;font-size:14px}.op-tbl th,.op-tbl td{text-align:left;padding:9px 12px;border-bottom:1px solid var(--line);vertical-align:middle}.op-tbl th{font:600 12px var(--body);text-transform:uppercase;letter-spacing:.08em;color:var(--dim);white-space:nowrap}.op-tbl tr:last-child td{border-bottom:0}.op-tbl td.n,.op-tbl th.n{text-align:right;font-variant-numeric:tabular-nums}.op-tbl small{display:block;color:var(--dim)}.op-counts{display:flex;flex-wrap:wrap;gap:8px 10px;margin:0 0 14px}.op-bar{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:0 0 14px}.op-bar input,.op-bar select,.op-tbl select,.op-tbl input[type=date]{font:500 14px var(--body);color:var(--ink);background:var(--card);border:1.5px solid var(--line2);border-radius:10px;padding:8px 10px;min-height:40px}.op-bar input[type=search]{flex:1 1 220px;max-width:340px}.op-subj{position:relative}.op-subj summary{cursor:pointer;font-size:13px;color:var(--ink);list-style:none}.op-subj summary::-webkit-details-marker{display:none}.op-subj[aria-disabled=true] summary{color:var(--dim);cursor:default}.op-subj .op-menu{position:absolute;z-index:5;left:0;top:100%;min-width:230px;max-height:300px;overflow:auto;background:var(--card);border:1px solid var(--line2);border-radius:10px;box-shadow:var(--sh2);padding:6px}.op-subj label{display:flex;gap:8px;align-items:center;padding:4px 6px;font-size:13.5px;white-space:nowrap}.op-toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);background:var(--navy);color:var(--on-navy);padding:10px 18px;border-radius:10px;font-size:14.5px;z-index:60;box-shadow:var(--sh2);max-width:90vw}.op-toast.err{background:var(--bad-t);color:#fff}.op-more{margin:14px 0 0}.op-pre{white-space:pre-wrap;word-break:break-word;max-height:320px;overflow:auto;background:var(--tint);border:1px solid var(--line);border-radius:8px;padding:10px 12px;font:12.5px/1.45 ui-monospace,Menlo,monospace;margin:4px 0 12px}.op-cj>td{background:var(--paper)}.op-two{display:grid;grid-template-columns:minmax(0,5fr) minmax(0,7fr);gap:28px;align-items:start}@media(max-width:900px){.op-two{grid-template-columns:1fr}}.op-left{position:sticky;top:84px}.op-two h4{margin:18px 0 6px;font-size:15px}.op-files{list-style:none;padding:0;margin:0}.op-files li{padding:6px 0;border-bottom:1px solid var(--line)}.op-box{border:1px solid var(--line2);border-radius:10px;padding:12px;margin:8px 0;position:relative;background:var(--paper)}.op-box label,.op-fld label{display:block;font:600 12px var(--body);text-transform:uppercase;letter-spacing:.06em;color:var(--dim);margin:8px 0 3px}.op-ed,.op-note,#rvTutor{width:100%;font:14.5px/1.45 var(--body);color:var(--ink);background:var(--paper);border:1px solid var(--line2);border-radius:8px;padding:8px 10px;box-sizing:border-box}.op-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px}.op-del{position:absolute;right:10px;top:8px;color:var(--bad-t)}.op-over{color:var(--bad-t);font-weight:700}.op-ok{color:var(--ok-t);font-weight:700}.op-viol{margin:4px 0 10px;padding-left:20px;color:var(--bad-t)}.op-btns{display:flex;gap:10px;flex-wrap:wrap;margin:14px 0 30px}/* Past-paper analysis: table-based charts that sit on paper cards on the dark desk. */.sr{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}.achart{padding:22px 20px 20px}.achart h3{margin:0 0 12px;font-size:18px}.achart .note{margin-top:12px}.tscroll{overflow-x:auto;max-width:100%;-webkit-overflow-scrolling:touch}.tscroll:focus-visible{outline:2px solid var(--coral-ink);outline-offset:2px;border-radius:6px}table.at{width:100%;border-collapse:collapse;font-size:14.5px;color:var(--ink)}table.at th,table.at td{padding:6px 10px 6px 0;text-align:left;vertical-align:middle;border-bottom:1px solid var(--line)}table.at thead th{font:500 11.5px var(--mono);text-transform:uppercase;letter-spacing:.05em;color:var(--ink-2);border-bottom:1.5px solid var(--ink);vertical-align:bottom}table.at tbody th{font-weight:500;color:var(--ink);width:44%;min-width:9.5em;line-height:1.3}table.at tbody tr:last-child th,table.at tbody tr:last-child td{border-bottom:0}table.at td.sh{font:500 13px var(--mono);white-space:nowrap}.bc{display:flex;align-items:center;gap:8px;min-width:130px}.bc .tr{flex:1;min-width:0;height:14px;background:var(--tint);border-radius:3px;overflow:hidden}.bc i{display:block;height:100%;background:var(--coral);border-radius:3px}.bc b{font:500 13px var(--mono);color:var(--ink);min-width:3.4em;text-align:right;white-space:nowrap}.bc i.s1{background:var(--s1)}.bc i.s2{background:#d9a437}.sw{display:inline-block;width:10px;height:10px;border-radius:2px;margin-right:6px;background:var(--coral)}.sw.s1{background:var(--s1)}.sw.s2{background:#d9a437}table.grp{min-width:420px}table.grp.g3{min-width:560px}table.grp td{padding-right:14px}table.grp .bc{min-width:100px}table.heat{min-width:460px}table.heat td.hm{text-align:center;font:500 13px var(--mono);padding:8px 6px;border:2px solid var(--paper);color:var(--ink)}table.heat thead th{text-align:center}table.heat thead th:first-child{text-align:left}.stack{display:grid;gap:18px;align-content:start}.stack .card h3{margin:0 0 8px}.stack .card h3 a{color:var(--ink)}.panel .ticks li{color:var(--text)}.hero .prose .note a{color:var(--lamp)}@media(max-width:700px){.achart{padding:18px 14px 16px}table.at{font-size:14px}table.at tbody th{min-width:8em}}/* lean sweep: top-10 bars with a toggle, navy stat strip, 3-step revise box, hub subject tiles */.achart.cut:not(.open) tr.xtra{display:none}.atoggle{margin:12px 0 0;padding:8px 16px;font-size:14px}.astrip{list-style:none;margin:22px 0 0;padding:0;display:flex;flex-wrap:wrap;gap:0;background:var(--frame);color:var(--frame-ink);border-radius:var(--rl);overflow:hidden;width:max-content;max-width:100%}.astrip li{padding:12px 20px;font:700 15px var(--head);border-right:1px solid rgba(255,255,255,.18)}.astrip li:last-child{border-right:0}.asteps{list-style:none;margin:0 0 18px;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.asteps li{display:flex;gap:12px;align-items:center;padding:14px 16px;border:1px solid var(--line);border-left:4px solid var(--frame);border-radius:var(--rl);background:var(--card)}.asteps b{flex:none;display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:var(--frame);color:var(--frame-ink);font:700 14px var(--head)}.asteps span{font-size:15px}.atiles{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px}.atile{display:grid;align-content:start;gap:6px;padding:20px;border:1px solid var(--line);border-top:3px solid var(--frame);border-radius:var(--rl);background:var(--card)}.atile h3{margin:0;font-size:22px}.atile p{margin:0;color:var(--dim)}.abtns{display:flex;gap:8px;margin-top:10px!important}.abtns .btn{padding:9px 18px;font-size:14.5px}@media(max-width:760px){.asteps{grid-template-columns:1fr}.astrip li{padding:10px 14px;font-size:14px}}/* Blog: /blog/ index cards and post covers (content/blog.html, content/blog/*.html) */.blog-cover{margin:26px 0 0;border-radius:var(--rl);overflow:hidden;border:1px solid var(--line);box-shadow:var(--sh1);background:#fff}.blog-cover img{display:block;width:100%;height:auto}.blog-grid{display:grid;gap:22px}@media(min-width:700px){.blog-grid{grid-template-columns:1fr 1fr}}@media(min-width:1040px){.blog-grid{grid-template-columns:repeat(3,1fr)}}.blog-card{display:flex;flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1);overflow:hidden;color:var(--text);text-decoration:none;transition:box-shadow .2s,transform .2s}.blog-card:hover{box-shadow:var(--sh2);transform:translateY(-2px)}.blog-card img{display:block;width:100%;height:auto;aspect-ratio:1200/630;background:#fff;border-bottom:1px solid var(--line)}.blog-card .bc-body{padding:18px 20px 22px;display:flex;flex-direction:column;gap:8px;flex:1}.blog-card .bc-tag{font:600 11.5px var(--body);text-transform:uppercase;letter-spacing:.07em;color:var(--coral-ink)}.blog-card h2{font:700 19px/1.3 var(--head);margin:0;color:var(--ink)}.blog-card p{margin:0;color:var(--ink-2);font-size:15px;line-height:1.55}.blog-card .bc-meta{margin-top:auto;padding-top:6px;font-size:13px;color:var(--mute)}.blog-feature{display:grid;gap:0}@media(min-width:900px){.blog-feature{grid-template-columns:1.25fr 1fr}.blog-feature img{border-bottom:0;border-right:1px solid var(--line);align-self:center}.blog-feature .bc-body{padding:30px 32px;justify-content:center}.blog-feature h2{font-size:26px}}/* Inline SVG figures in posts: always on white so the diagram colours work in dark mode */.fig{margin:28px 0;padding:18px;background:#fff;border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1)}.fig svg{display:block;width:100%;height:auto;max-width:100%}.fig figcaption{margin-top:12px;font-size:14px;line-height:1.5;color:#47536d}.prose .panel{margin:26px 0}.prose .table-wrap,.prose .tbl{overflow-x:auto;-webkit-overflow-scrolling:touch}.author-box{display:grid;grid-template-columns:96px 1fr;gap:22px;align-items:start;background:var(--card);border:1px solid var(--line);border-left:3px solid var(--gold);border-radius:var(--rl);box-shadow:var(--sh1);padding:24px}.author-box img{width:96px;height:128px;object-fit:cover;border-radius:12px}.author-box h2{margin:2px 0 8px;font-size:22px}.author-box p{color:var(--ink-2);font-size:15.5px}.author-box .author-links{display:flex;flex-wrap:wrap;gap:8px 20px;margin:4px 0 0;font-weight:600}.author-box a{color:var(--coral-ink)}@media(max-width:560px){.author-box{grid-template-columns:1fr}.author-box img{width:72px;height:96px}}.blog-chips{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 6px}.blog-chips button{font:600 13px var(--body);border:1px solid var(--line2);background:var(--card);border-radius:999px;padding:6px 14px;color:var(--ink-2);cursor:pointer}.blog-chips button[aria-pressed=true]{background:var(--navy);border-color:var(--navy);color:var(--on-navy)}.blog-grp{margin:34px 0 0}.blog-grp[hidden],.blog-card[hidden]{display:none}.blog-h{font-size:clamp(22px,2.4vw,28px);margin:0 0 16px;padding-left:12px;border-left:4px solid var(--navy)}/* IB grade boundaries (/ib-grade-boundaries/) */.bd-hero{padding-bottom:20px}.bd-hero h1{font-size:clamp(34px,4.6vw,58px);max-width:20ch}.bd-pill{display:inline-block;font:500 13px var(--mono);color:var(--on-navy);background:var(--navy);border-radius:999px;padding:5px 14px}.bd-filters-sec{padding-top:30px}.bd-filters{display:flex;flex-wrap:wrap;gap:12px 24px;margin:0 0 26px;padding:14px 16px;background:var(--desk-2);border:1px solid var(--edge);border-radius:16px}.bd-filters[hidden]{display:none}.bd-f{display:flex;flex-wrap:wrap;align-items:center;gap:6px}.bd-f>span{font:500 12px var(--mono);color:var(--dim);text-transform:uppercase;letter-spacing:.08em;margin-right:6px}.bd-f button,.bd-tz{font:600 14px var(--body);color:var(--text);background:transparent;border:1.5px solid var(--line2);border-radius:999px;padding:8px 14px;min-height:40px;cursor:pointer}.bd-f button[aria-pressed=true],.bd-tz.on{background:var(--navy);border-color:var(--navy);color:var(--on-navy)}.bd-tiles{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px;margin-top:18px}.bd-tile{display:grid;gap:4px;align-content:start;min-width:0;padding:18px;background:var(--desk-3);border:1px solid var(--edge);border-radius:18px;text-decoration:none;color:var(--text);transition:transform .15s,border-color .15s}.bd-tile:hover{transform:translateY(-2px);border-color:var(--gold-b)}.bd-tile[hidden]{display:none}.bd-tn{font:700 20px var(--head);letter-spacing:-.03em}.bd-tl{font:500 12px var(--mono);color:var(--dim);text-transform:uppercase;letter-spacing:.06em;margin-top:6px}.bd-tv{font:500 14px var(--mono);color:var(--dim)}.bd-tv b{font:800 22px var(--head);color:var(--lamp);letter-spacing:-.03em}.bd-spark{width:100%;max-width:150px;height:38px;margin:6px 0 2px}.bd-spark polyline{fill:none;stroke:var(--lamp);stroke-width:2;stroke-linejoin:round;stroke-linecap:round}.bd-spark circle{fill:var(--coral)}.bd-d{font:500 12.5px var(--mono);color:var(--dim)}.bd-d.up{color:var(--bad-t)}.bd-d.down{color:var(--ok-t)}.bd-empty{color:var(--dim)}.bd-sub{padding-top:30px}.bd-sub h2{max-width:26ch}.bd-course{margin:0;padding:0;background:none;border:0;border-top:1px solid var(--line);border-radius:0;box-shadow:none}.bd-course[hidden]{display:none}.bd-course summary{display:flex;flex-wrap:wrap;align-items:baseline;gap:4px 14px;padding:14px 54px 14px 4px;position:relative;cursor:pointer}.bd-course summary:hover .bd-sn{color:var(--coral-ink)}.bd-sn{font:700 18px var(--head);letter-spacing:-.02em}.bd-ss{font:500 13px var(--mono);color:var(--ink-2)}.bd-course summary:after{right:8px;top:50%;transform:translateY(-50%)}.bd-body{padding:6px 4px 22px;color:var(--text);min-width:0}.bd-body h3{font-size:22px;margin-bottom:.6em}.bd-sum,.bd-gap{color:var(--dim);max-width:70ch}.bd-sum b,.bd-gap b{color:var(--text)}.bd-ctl{display:flex;flex-wrap:wrap;gap:10px 16px;align-items:center;margin:14px 0 6px}.bd-ctl[hidden]{display:none}.bd-ctl label{display:flex;align-items:center;gap:8px;font:500 13px var(--mono);color:var(--dim)}.bd-ctl select{font:600 15px var(--body);color:var(--text);background:var(--desk-2);border:1.5px solid var(--line2);border-radius:10px;padding:8px 12px;min-height:40px}.bd-tzs{display:flex;flex-wrap:wrap;gap:6px}.bd-read{font:500 13px var(--mono);color:var(--dim);margin:6px 0 10px;min-height:1.6em}.bd-read b{color:var(--lamp)}.bd-gc{display:inline-block;margin:0 10px 2px 0}.bd-gc b{color:var(--text)}.bd-cw{overflow-x:auto;background:var(--desk-2);border:1px solid var(--edge);border-radius:14px;padding:8px}.bd-chart[hidden],.bd-none[hidden]{display:none}.bd-none{color:var(--dim);margin:20px}.bd-svg{display:block;width:100%;min-width:480px;height:auto}.bd-grid{stroke:var(--edge);stroke-width:1}.bd-ax{fill:var(--dim);font:12px var(--mono)}.bd-end{font:700 13px var(--mono)}.bd-ln{fill:none;stroke-width:2.2;stroke-linejoin:round;stroke-linecap:round}.bd-col{fill:transparent;cursor:pointer}.bd-col:hover{fill:rgba(27,42,74,.05)}.bd-col.on{fill:var(--gold-t)}.bd-leg{list-style:none;display:flex;flex-wrap:wrap;gap:6px 16px;margin:10px 0 18px;padding:0;font:500 12.5px var(--mono);color:var(--dim)}.bd-leg i{display:inline-block;width:10px;height:10px;border-radius:50%;margin-right:6px}.bd-tw{overflow:auto;max-height:440px;border:1px solid var(--edge);border-radius:12px;max-width:100%}.bd-table{width:100%;min-width:520px;border-collapse:collapse;font:500 14px var(--mono)}.bd-table th,.bd-table td{padding:9px 10px;text-align:center;border-bottom:1px solid var(--edge);white-space:nowrap}.bd-table thead th{position:sticky;top:0;background:var(--desk-2);color:var(--dim);font-size:12px;z-index:1}.bd-table tbody th{text-align:left;font-weight:500;color:var(--text)}.bd-table td.g7{color:var(--lamp);font-weight:700}.bd-table tr.sel{background:var(--gold-t)}.bd-table tr[hidden]{display:none}.bd-links{display:flex;flex-wrap:wrap;gap:10px 18px;align-items:center;margin:18px 0 0}.bd-links a:not(.btn){font-size:15px}.bd-cta{display:flex;flex-wrap:wrap;gap:18px 30px;align-items:center;justify-content:space-between;padding:clamp(22px,3vw,34px);background:var(--desk-3);border:1px solid var(--edge);border-left:4px solid var(--lamp);border-radius:20px}.bd-cta h2{font-size:clamp(24px,3vw,34px);margin-bottom:.3em}.bd-cta p{margin:0 0 6px;color:var(--dim)}.bd-src{margin-top:18px}@media(max-width:560px){.bd-course summary{padding-right:46px}.bd-body{padding-inline:14px}.bd-filters{padding:12px}}/* Grade 7 at a glance: one framed panel with a subject switcher (owner, 2026-10-21; replaces the 10-tile grid) */.g7{margin-top:18px}.g7bar{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px;margin-bottom:14px}.g7tabs{display:flex;gap:6px;padding:5px;background:var(--band);border:1px solid var(--band-line);border-radius:14px;overflow-x:auto;scrollbar-width:none;max-width:100%}.g7tabs::-webkit-scrollbar{display:none}.g7tabs button,.g7lv button{flex:none;font:700 14.5px var(--body);color:var(--ink-2);background:none;border:0;border-radius:10px;padding:10px 16px;min-height:42px;cursor:pointer;white-space:nowrap}.g7tabs button[aria-selected=true],.g7lv button[aria-pressed=true]{background:var(--frame);color:var(--frame-ink);box-shadow:var(--sh1)}.g7lv{display:flex;gap:4px;padding:5px;background:var(--band);border:1px solid var(--band-line);border-radius:14px}.g7lv button:disabled{opacity:.35;cursor:default}.g7stage{position:relative}.g7p{background:var(--card);border:1px solid var(--band-line);border-radius:18px;box-shadow:var(--sh2);overflow:hidden;animation:g7in .3s both}.g7p[hidden]{display:none}@keyframes g7in{from{opacity:.4;transform:translateX(10px)}}.g7p header{display:flex;flex-wrap:wrap;align-items:baseline;gap:6px 16px;padding:16px 22px;background:var(--band);border-bottom:1px solid var(--band-line);border-left:5px solid var(--frame)}.g7p h3{margin:0;font:800 24px var(--head);letter-spacing:-.02em}.g7b{font:600 12.5px var(--body);text-transform:uppercase;letter-spacing:.08em;color:var(--mute)}.g7m{display:grid;gap:18px 30px;padding:22px;align-items:center}@media(min-width:860px){.g7m{grid-template-columns:minmax(260px,.8fr) 1.2fr}}.g7ss{display:grid;grid-template-columns:repeat(auto-fit,minmax(80px,1fr));gap:10px;margin-bottom:12px}.g7s{border:1px solid var(--band-line);border-radius:14px;padding:12px 14px;display:flex;flex-wrap:wrap;align-items:baseline;gap:0 2px;background:var(--card)}.g7s span{width:100%;font:700 12px var(--body);letter-spacing:.08em;color:var(--mute)}.g7s b{font:800 34px/1.1 var(--head);color:var(--lamp);letter-spacing:-.03em}.g7s i{font-style:normal;font-weight:700;color:var(--lamp)}.g7m .bd-d{font-size:14px;display:inline-block;padding:4px 10px;border-radius:999px;background:var(--band)}.g7n{font-size:13.5px;color:var(--mute);margin:12px 0 0}.g7r{min-width:0}.g7c{width:100%;height:auto;display:block}.g7c .gr line{stroke:var(--band-line);stroke-width:1}.g7c text{font:500 11px var(--body);fill:var(--mute)}.g7c .ar{fill:var(--gold-t)}.g7c polyline{fill:none;stroke:var(--lamp);stroke-width:2.6;stroke-linejoin:round;stroke-linecap:round}.g7c circle{fill:var(--card);stroke:var(--lamp);stroke-width:2}.g7c circle.last{fill:var(--lamp)}.g7c text.v{font:700 11.5px var(--body);fill:var(--ink)}.g7p footer{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:12px;padding:14px 22px;border-top:1px solid var(--band-line)}.g7p footer a:not(.btn){font-weight:600;color:var(--coral-ink)}.g7nav{position:absolute;top:50%;z-index:2;width:42px;height:42px;margin-top:-21px;border-radius:50%;border:1px solid var(--band-line);background:var(--card);box-shadow:var(--sh2);font:400 26px/1 var(--body);color:var(--ink);cursor:pointer}.g7nav.prev{left:-20px}.g7nav.next{right:-20px}.g7dots{display:flex;justify-content:center;gap:6px;margin-top:14px}.g7dots i{width:7px;height:7px;border-radius:50%;background:var(--line2);transition:.2s}.g7dots i.on{width:22px;border-radius:4px;background:var(--frame)}.bd-all{padding-top:10px}@media(max-width:700px){.g7nav{display:none}.g7bar{flex-direction:column;align-items:stretch}.g7lv{align-self:flex-start}.g7m{padding:16px}.g7p header{padding:14px 16px}.g7s b{font-size:28px}}@media(prefers-reduced-motion:reduce){.g7p{animation:none}}/* lean list: one framed panel per subject group, courses as rows that open their chart and table */.bd-sub{background:var(--card);border:1px solid var(--line);border-top:3px solid var(--frame);border-radius:var(--rl);padding:6px 20px 8px;margin:0 0 16px}.bd-sub .bd-course:first-of-type{border-top:0}.bd-sub[hidden]{display:none}.bd-grp{margin:12px 0 2px!important}.bd-all{padding-top:30px}.bd-hero{padding-bottom:0}.bd-all .note{margin:0 0 14px}/* Free notes: a readable sheet of paper on the night desk. */.cs-width{max-width:calc(76ch + 96px);min-width:0}.cs-hero{padding-bottom:30px}.cs-hero h1{font-size:clamp(32px,4.8vw,57px);line-height:1.12;overflow-wrap:anywhere}.cs-hero .lede{max-width:76ch}.cs-hero .pills{margin-bottom:0}.cs-body{padding-bottom:64px}.cs-article{padding:clamp(20px,4.5vw,48px);color:var(--ink);overflow-wrap:anywhere;--navy:var(--ink);--navy-deep:var(--ink);--gold:var(--coral-ink)}.cs-article p,.cs-article li,.cs-article td,.cs-article .faq-answer{color:var(--ink-2)}.cs-article strong,.cs-article b,.cs-article h2,.cs-article h3,.cs-article h4{color:var(--ink)}.cs-article h2{font-size:clamp(23px,3vw,31px);line-height:1.3;margin:1.7em 0 .7em;scroll-margin-top:90px}.cs-article h2:first-child{margin-top:0}.cs-article h3{font-size:20px;line-height:1.4;margin:1.4em 0 .6em}.cs-article h4{font:700 17px/1.4 var(--head);margin:.7em 0}.cs-article li{margin-bottom:.6em}.cs-article ul,.cs-article ol{padding-left:1.5em}.cs-article a:focus-visible,.cs-article summary:focus-visible{outline-color:var(--coral-ink)}.cs-article code{background:var(--line);color:var(--ink);white-space:normal}.cs-article .syl-tag{display:inline-block;border:1px solid var(--line);border-radius:999px;padding:3px 8px;font:500 11px/1.5 var(--mono);color:var(--coral-ink);vertical-align:middle;letter-spacing:0}.cs-article .formula-row{display:grid;grid-template-columns:minmax(120px,30%) minmax(0,1fr);gap:4px 18px;align-items:baseline;border-bottom:1px solid var(--line);padding:13px 4px;margin:0;min-width:0;overflow-x:auto;overflow-y:hidden;color:var(--ink)}.cs-article :not(.formula-row)+.formula-row{border-top:1px solid var(--line);margin-top:14px}.cs-article .formula-row+:not(.formula-row){margin-top:22px}.cs-article .formula-row:hover{background:color-mix(in srgb,var(--hl) 14%,transparent)}@media(max-width:560px){.cs-article .formula-row{grid-template-columns:minmax(0,1fr);padding:12px 2px}}.cs-article .formula-row__label{font:500 12px/1.5 var(--mono);color:var(--ink-2)}.cs-article .katex{font-size:1.03em}.cs-article .katex-display{max-width:100%;overflow-x:auto;overflow-y:hidden;padding:6px 0;margin:.7em 0}.cs-article .katex-display>.katex{white-space:nowrap}.cs-article .callout{border-left:4px solid var(--coral);padding:16px 18px;background:color-mix(in srgb,var(--coral) 7%,var(--paper));margin:20px 0;border-radius:0 10px 10px 0;color:var(--ink-2)}.cs-article .callout--trick{border-color:var(--lamp);background:color-mix(in srgb,var(--lamp) 17%,var(--paper))}.cs-article .callout--note{border-color:var(--ink-2);background:color-mix(in srgb,var(--ink) 4%,var(--paper))}.cs-article .worked-example{padding:clamp(16px,3vw,26px);border:1px solid var(--line);border-top:4px solid var(--coral);border-radius:10px;margin:28px 0}.cs-article .worked-example__title{font:700 16px/1.5 var(--head);color:var(--coral-ink);margin-bottom:12px}.cs-article .cs-table{max-width:100%;overflow-x:auto;margin:20px 0;border:1px solid var(--line);border-radius:10px}.cs-article table{border-collapse:collapse;width:100%;font-size:14px;line-height:1.55}.cs-article th,.cs-article td{padding:12px 14px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line);min-width:130px}.cs-article th{font-weight:700;color:var(--ink);background:color-mix(in srgb,var(--ink) 5%,var(--paper))}.cs-article tr:last-child td{border-bottom:0}.cs-article details{border:1px solid var(--line);padding:17px;margin:12px 0}.cs-article summary{line-height:1.55;display:block}.cs-article summary:after{float:right;margin-left:10px}.cs-article .faq-answer{padding-top:14px}.cs-article .diagram,.cs-article .cheatsheet-diagram-wrap{background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px;margin:24px 0;max-width:100%;overflow-x:auto}.cs-article svg{display:block;max-width:100%;height:auto;margin:auto}.cs-article svg.cs-raster{width:100%}.cs-article .diagram__cap,.cs-article .cheatsheet-caption{font-size:14px;line-height:1.6;color:var(--ink-2);margin:14px 0 0}.cs-article .exam-bank{border:1px solid var(--line);border-radius:10px;margin:22px 0;overflow:hidden}.cs-article .exam-bank__head{display:flex;align-items:center;gap:10px;padding:12px 16px;background:var(--ink);color:var(--paper);font:500 12px/1.6 var(--mono)}.cs-article .exam-bank__head svg{width:18px;margin:0}.cs-article .exam-bank__body{padding:18px}.cs-article .exam-bank__tests{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:14px}.cs-article .exam-bank__tests span,.cs-article .exam-freq{font:500 11px/1.6 var(--mono);background:var(--navy);color:var(--on-navy);padding:3px 7px;border-radius:6px}.cs-article .exam-bank__tip{border-top:1px solid var(--line);padding:12px 0;color:var(--ink-2)}.cs-article .related-strip{border-top:1px solid var(--line);margin-top:32px;padding-top:8px}.cs-article .related-strip__links{display:flex;gap:10px;flex-wrap:wrap}.cs-article .related-strip__links a{font-size:14px}.cs-article .theme-block{margin:26px 0}.cs-article .theme-header{border-bottom:1px solid var(--line);margin-bottom:16px}.cs-article .theme-letter{font:500 12px var(--mono);color:var(--coral-ink)}.cs-article .theme-title{margin-top:8px}.cs-article .topic-grid{display:grid;gap:12px}.cs-article .topic-card{display:block;border:1px solid var(--line);border-radius:12px;padding:18px;text-decoration:none;min-width:0}.cs-article .topic-card:hover{border-color:var(--coral-ink)}.cs-article .topic-card__free,.cs-article .topic-card__num,.cs-article .topic-card__meta{font:500 11px/1.6 var(--mono);color:var(--coral-ink)}.cs-article .topic-card__free{float:right}.cs-article .topic-card__desc{font-size:14px}.cs-article .topic-card__meta{display:flex;flex-wrap:wrap;justify-content:space-between;gap:6px}.cs-article .topic-card__meta__cta svg{display:inline-block;width:14px;vertical-align:middle}.cs-going{padding:40px 0 28px}.cs-going h2{font-size:30px}.cs-links{display:grid;gap:12px;grid-template-columns:repeat(2,minmax(0,1fr));margin-top:20px}.cs-links a{display:block;border:1px solid var(--edge);border-radius:12px;padding:18px;text-decoration:none;color:var(--text);overflow-wrap:anywhere}.cs-links a:hover{border-color:var(--lamp)}.cs-links small{display:block;font:500 11px/1.6 var(--mono);color:var(--lamp);margin-bottom:7px}.cs-live h2{font-size:21px;line-height:1.45;max-width:36ch}.cs-live p{margin-bottom:0}@media(min-width:768px){.cs-article .topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:480px){.cs-links{grid-template-columns:1fr}.cs-article{padding:22px 18px}.cs-article .worked-example{padding:14px}.cs-article .callout{padding:14px}.cs-article table{font-size:13px}}.cs-article .callout>strong:first-child{display:block;font:500 11.5px/1.4 var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--coral-ink);margin-bottom:6px}.cs-article .callout--trap{border-color:var(--coral)}.cs-article{overflow-x:clip}.cs-article .katex-mathml{max-width:100%;overflow:hidden}.cs-article p .katex,.cs-article li .katex{white-space:normal}.cs-article,.cs-article .cs-table,.cs-article .katex-display,.cs-article .formula-row,.cs-article .diagram{position:relative}.avatar-photo{width:84px;height:112px;object-fit:cover;object-position:top;border-radius:14px;box-shadow:var(--sh1)}.trust{grid-template-columns:1fr}@media(min-width:900px){.trust{grid-template-columns:1.1fr .9fr .8fr}}.quotes{display:grid;gap:12px;align-content:start}.quotes blockquote{margin:0;background:var(--paper);color:var(--ink);border-radius:12px;padding:16px 18px;box-shadow:var(--sh1)}.quotes blockquote p{margin:0 0 6px;font-size:15px;line-height:1.5}.quotes cite{font:500 12px var(--mono);font-style:normal;color:var(--ink-2)}.quotes .note a{color:var(--lamp)}.certs{display:grid;gap:14px;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));margin:12px 0 4px}.certs figure{margin:0}.certs img{border-radius:10px;box-shadow:var(--sh1)}.certs figcaption{font-size:13.5px;color:var(--dim);margin-top:6px}.author-hero{display:grid;gap:26px;align-items:center}@media(min-width:760px){.author-hero{grid-template-columns:200px 1fr}}.author-hero img{border-radius:18px;box-shadow:var(--sh1)}/* Lean content components (about, author, EE, method, legal): navy frame, icon tiles, stat band */.statband{display:grid;grid-template-columns:repeat(4,1fr);background:var(--frame);color:var(--frame-ink);border-radius:14px;overflow:hidden;margin:6px 0 0}.statband div{padding:18px 12px;text-align:center;border-right:1px solid rgba(255,255,255,.16)}.statband div:last-child{border:0}.statband b{display:block;font:800 clamp(24px,3vw,34px)/1.1 var(--head)}.statband span{font-size:13.5px;opacity:.88}.tiles{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:16px;margin:0}.tile{border:1px solid var(--band-line);border-top:3px solid var(--frame);border-radius:12px;padding:20px;background:var(--card)}.tile .ti{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:var(--frame);color:var(--frame-ink);margin-bottom:12px}.tile .ti svg{width:24px;height:24px}.tile h2,.tile h3{font-size:19px;margin:0 0 6px}.tile p{margin:0;color:var(--dim);font-size:15px}.tile a{font-weight:600}.tickrow{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:10px 22px}.tickrow li{position:relative;padding-left:28px;color:var(--ink-2);font-size:15px}.tickrow li:before{content:"";position:absolute;left:0;top:3px;width:18px;height:18px;border-radius:50%;background:var(--frame) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 18 18'%3E%3Cpath d='M5 9.5l2.5 2.5L13 6.5' fill='none' stroke='white' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center/100% no-repeat}.pillcta{display:inline-flex;align-items:center;gap:8px;border:1.5px solid var(--frame);border-radius:999px;padding:10px 20px;font-weight:700;text-decoration:none;color:var(--ink)}.pillcta:hover{background:var(--frame);color:var(--frame-ink)}.badges{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0 0;padding:0;list-style:none}.badges li{background:var(--frame);color:var(--frame-ink);border-radius:999px;padding:5px 13px;font:600 13px var(--body)}.profile{display:grid;gap:26px;align-items:center;border:1px solid var(--band-line);border-top:3px solid var(--frame);border-radius:16px;background:var(--band);padding:24px}@media(min-width:760px){.profile{grid-template-columns:200px 1fr}}.profile img{border-radius:14px;box-shadow:var(--sh1)}.certs figure{border:1px solid var(--band-line);border-radius:12px;padding:8px;background:var(--card)}.navypanel{background:var(--frame);border-radius:14px;padding:22px;color:var(--frame-ink)}.navypanel h2{color:var(--frame-ink);margin-top:0}.navypanel .quotes{grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}.shelf{display:flex;gap:16px;overflow-x:auto;scroll-snap-type:x mandatory;padding:4px 2px 14px;margin:0;list-style:none}.shelf li{flex:0 0 150px;scroll-snap-align:start}@media(min-width:900px){.shelf{flex-wrap:wrap;overflow:visible}.shelf li{flex:0 0 calc(16.66% - 14px)}}.shelf a{display:block;text-decoration:none;color:var(--ink);font:600 13.5px/1.3 var(--body)}.shelf img{width:100%;height:auto;border-radius:6px;box-shadow:var(--sh1);margin-bottom:8px;display:block}.flow{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:14px;counter-reset:f;list-style:none;padding:0;margin:0}.flow li{counter-increment:f;position:relative;border:1px solid var(--band-line);border-top:3px solid var(--frame);border-radius:12px;padding:18px;background:var(--card)}.flow li:before{content:counter(f);position:absolute;top:-16px;right:14px;width:30px;height:30px;border-radius:50%;background:var(--frame);color:var(--frame-ink);display:grid;place-items:center;font:700 14px var(--body)}.flow b{display:block;font:700 17px var(--head);margin:8px 0 4px;color:var(--ink)}.flow span{color:var(--dim);font-size:14.5px}.flow .ti{display:grid;place-items:center;width:40px;height:40px;border-radius:11px;background:var(--frame);color:var(--frame-ink)}.flow .ti svg{width:22px;height:22px}.limits{border-left:4px solid var(--frame);background:var(--band);border-radius:0 12px 12px 0;padding:16px 20px}.legal{border:1px solid var(--band-line);border-left:5px solid var(--frame);border-radius:12px;background:var(--card);padding:10px clamp(18px,3vw,36px) 20px}.legal h2:first-child{margin-top:18px}.badge-upd{display:inline-block;background:var(--frame);color:var(--frame-ink);border-radius:999px;padding:4px 12px;font:600 12.5px var(--body);margin:0 0 4px}@media(max-width:640px){.statband{grid-template-columns:1fr 1fr}.statband div:nth-child(2){border-right:0}.statband div:nth-child(-n+2){border-bottom:1px solid rgba(255,255,255,.16)}}/* Notebook page shell for content pages (Extended Essay): ruled paper, red margin line, pen accents (font and colours come from the page head) */.nbk{background-image:linear-gradient(90deg,transparent 46px,var(--margin-rule) 46px,var(--margin-rule) 48px,transparent 48px),repeating-linear-gradient(transparent 0 31px,var(--rule) 31px 32px)}@media(max-width:700px){.nbk{background-image:repeating-linear-gradient(transparent 0 31px,var(--rule) 31px 32px)}}.nbk .hero,.nbk .section,.nbk section{background:transparent}.nbk .pen{font:700 22px/1.1 "Caveat",cursive;color:var(--pen)}.crit5{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px;list-style:none;padding:0;margin:14px 0}.crit5 li{background:var(--paper);border:1px solid var(--line2);border-top:3px solid var(--frame);border-radius:12px;padding:14px 16px;position:relative}.crit5 .L{font:700 40px/1 "Caveat",cursive;color:var(--pen)}.crit5 .M{position:absolute;top:12px;right:12px;background:var(--frame);color:var(--frame-ink);border-radius:999px;font:700 12px var(--body);padding:3px 10px}.crit5 b{display:block;font:700 15.5px var(--head);color:var(--ink);margin:4px 0}.crit5 span.d{font-size:14px;color:var(--dim)}.crit5 li.top{border-top-color:var(--pen)}.navypanel p,.prose .navypanel p{color:var(--frame-ink);opacity:.92}.navypanel .btn{color:var(--ink)}.navypanel .note{opacity:1}.flow{grid-template-columns:repeat(2,1fr)}@media(min-width:640px){.flow{grid-template-columns:repeat(4,1fr)}}/* annotated data booklet: plain = official, mint = ours */.db-hero .ctas{margin-top:22px}.db-key{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-bottom:18px}.db-key>div{display:flex;gap:12px;align-items:flex-start;background:var(--desk-2);border:1px solid var(--edge);border-radius:14px;padding:14px 16px}.db-key p{margin:0;font-size:14.5px;color:var(--dim);line-height:1.5}.db-key b{color:var(--text)}.sw{flex:none;width:22px;height:22px;border-radius:6px;margin-top:2px}.sw.plain{background:var(--paper)}.sw.note{background:var(--paper);box-shadow:inset 4px 0 0 var(--mint)}.sw.extra{background:var(--mint-bg2);border:2px solid var(--mint)}.db-toc ul{list-style:none;margin:0 0 22px;padding:0;display:flex;flex-wrap:wrap;gap:8px}.db-toc a{display:block;border:1px solid var(--edge);border-radius:999px;padding:7px 13px;font-size:13.5px;color:var(--text);text-decoration:none}.db-toc a:hover{border-color:var(--lamp);color:var(--lamp)}.db-article{padding:clamp(18px,4vw,44px);position:relative;overflow-x:clip;color:var(--ink)}.db-article h2{font-size:clamp(22px,2.8vw,30px);margin:1.6em 0 .6em;scroll-margin-top:90px;color:var(--ink)}.db-article section:first-of-type h2:first-child{margin-top:0}.db-article .db-theme{scroll-margin-top:80px}.db-article .db-theme>h2{border-top:2px solid var(--ink);padding-top:.8em;margin-top:1.8em}.db-table{border:1px solid var(--line2);border-radius:10px;overflow:hidden}.db-row{display:grid;grid-template-columns:minmax(150px,32%) minmax(0,1fr);border-top:1px solid var(--line)}.db-row:first-child{border-top:0}.db-row.one{grid-template-columns:minmax(0,1fr)}.db-k{padding:12px 14px;font-size:14.5px;color:var(--ink);background:var(--tint)}.db-v{padding:10px 14px;min-width:0}.db-where{display:block;font-size:13.5px;color:var(--ink-2)}.tx{color:var(--ink)}.tx.dm{display:block;overflow-x:auto;overflow-y:hidden;padding:4px 0;position:relative}.tx.dm .katex-display{margin:0}.tx.dm>.katex{text-align:left}.math-ready .tx.dm{font-size:1.08em}.db-note{margin:6px 0 2px;padding:6px 10px 6px 12px;border-left:4px solid var(--mint);background:var(--mint-bg);border-radius:0 8px 8px 0;font-size:13.5px;line-height:1.5;color:var(--mint-ink)}.db-note .who,.db-extra .who{display:block;font:500 10.5px/1.4 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--mint);margin-bottom:2px}.db-extra{margin:14px 0 6px;border:2px solid var(--mint);background:var(--mint-bg2);border-radius:12px;padding:12px 14px}.db-extra .who{margin-bottom:8px}.db-x{padding:8px 0;border-top:1px dashed var(--mint-b)}.db-x:first-of-type{border-top:0;padding-top:0}.db-x b{display:block;font:600 14px var(--head);color:var(--ok-t)}.db-x p{margin:4px 0 0;font-size:13.5px;color:var(--mint-ink);line-height:1.5}.db-x .tx{color:var(--ok-t)}.db-scroll{overflow-x:auto;border:1px solid var(--line2);border-radius:10px;position:relative}.db-tbl{border-collapse:collapse;width:100%;font-size:14.5px}.db-tbl th{background:var(--tint);text-align:left;padding:10px 12px;font-weight:700;color:var(--ink)}.db-tbl td{padding:9px 12px;border-top:1px solid var(--line);vertical-align:top;color:var(--ink)}.db-tbl td:first-child{min-width:150px}.db-tbl.si td,.db-tbl.si th{text-align:center}.db-symbols{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:10px}.db-symbols figure{margin:0;border:1px solid var(--line);border-radius:10px;padding:12px 10px 10px;text-align:center}.db-symbols svg{width:100%;max-width:130px;height:auto;fill:none;stroke:var(--ink);stroke-width:2;stroke-linecap:round;stroke-linejoin:round}.db-symbols svg text{fill:var(--ink);stroke:none;font:600 17px var(--body)}.db-symbols figcaption{font-size:13px;color:var(--ink-2);margin-top:6px}.db-spec .arrowline{display:flex;justify-content:space-between;font:500 12px var(--mono);color:var(--ink-2);margin:0 0 6px}.bands{display:grid;grid-template-columns:repeat(7,minmax(0,1fr));border:1px solid var(--line2);border-radius:10px;overflow:hidden}.band{padding:10px 8px;border-left:1px solid var(--line);min-width:0}.band:first-child{border-left:0}.band b{display:block;font-size:13.5px;color:var(--ink)}.band span{display:block;font:500 11px/1.4 var(--mono);color:var(--ink-2);margin-top:3px;overflow-wrap:anywhere}.band.b3{background:linear-gradient(90deg,#8a5cf6,#3b82f6,#22c55e,#facc15,#f97316,#ef4444);}.band.b3 b,.band.b3 span{color:#fff;text-shadow:0 1px 2px rgba(0,0,0,.5)}.vis{font-size:13.5px;color:var(--ink-2);margin:8px 0 0}.db-level{font:700 13px var(--body);background:var(--tint);color:var(--ink);padding:9px 12px;border-radius:8px;margin:18px 0 10px}.db-level.ahl{background:var(--ink);color:var(--paper)}.db-topic{display:grid;grid-template-columns:minmax(150px,26%) minmax(0,1fr);gap:4px 22px;padding:14px 0;border-top:1px solid var(--line)}.db-topic h3{font-size:17px;margin:4px 0 0;color:var(--ink)}.db-topic h3 small{font:500 10.5px var(--mono);background:var(--ink);color:var(--paper);border-radius:999px;padding:2px 7px;vertical-align:middle;margin-left:4px}.db-topic>.db-extra{grid-column:2}.db-eq{padding:6px 0;border-bottom:1px dotted var(--line);min-width:0}.db-eq:last-child{border-bottom:0}.db-empty{margin:4px 0;font-size:14px;color:var(--ink-2);font-style:italic}.db-foot{margin:30px 0 0;padding-top:16px;border-top:1px solid var(--line);font-size:13px;color:var(--ink-2);line-height:1.6}.print-only{display:none}@media(max-width:760px){.db-key{grid-template-columns:minmax(0,1fr)}.db-row,.db-topic{grid-template-columns:minmax(0,1fr)}.db-k{padding:10px 12px 4px;background:none;font-weight:600}.db-topic>.db-extra{grid-column:1}.bands{grid-template-columns:repeat(2,minmax(0,1fr))}.band{border-top:1px solid var(--line)}}@media print{@page{size:A4;margin:14mm 12mm 16mm}html,body{background:var(--card)!important}header.site,footer.site,.crumbs,.skip,.db-hero,.db-key,.db-toc,.db-more,script{display:none!important}.section,.wrap{padding:0!important;max-width:none!important}.db-article{box-shadow:none!important;border:0!important;padding:0!important;border-radius:0!important;background:var(--card)!important}.print-only{display:block;margin:0 0 10px;font-size:11px;color:var(--ink-2);border-bottom:2px solid #ff6a45;padding-bottom:6px}.db-theme{break-before:page}.db-topic,.db-row,.db-extra,.db-eq,.db-symbols figure,tr{break-inside:avoid}.db-note,.db-extra,.band.b3,.db-level.ahl,.sw{-webkit-print-color-adjust:exact;print-color-adjust:exact}.tx.dm{overflow:visible}}.tx.dm .katex-display{text-align:left}.tx.dm .katex-display>.katex{text-align:left}@media print{:root,html{color-scheme:light!important;background:var(--card)!important}body{font-size:12px}.db-article h2{font-size:19px;margin:1.1em 0 .45em}.db-row{grid-template-columns:34% minmax(0,1fr)}.db-k{padding:5px 8px;font-size:11.5px;background:var(--tint);font-weight:400}.db-v{padding:4px 8px}.db-where,.db-note,.db-x p,.db-tbl,.db-empty{font-size:10.5px}.db-note{padding:3px 8px;margin:3px 0 1px}.db-note .who,.db-extra .who{font-size:8.5px}.db-extra{padding:7px 10px;margin:8px 0 4px;border-radius:8px}.db-x{padding:4px 0}.db-x b{font-size:11.5px}.db-topic{grid-template-columns:24% minmax(0,1fr);gap:2px 14px;padding:7px 0}.db-topic h3{font-size:13px}.db-topic>.db-extra{grid-column:2}.db-eq{padding:2px 0}.math-ready .tx.dm{font-size:.95em}.db-tbl th,.db-tbl td{padding:4px 8px}.db-symbols{grid-template-columns:repeat(5,1fr);gap:6px}.db-symbols figure{padding:6px}.bands{grid-template-columns:repeat(7,1fr)}.db-level{padding:5px 9px;margin:10px 0 6px;font-size:11px}#circuits{break-before:page}}@media print{.db-topic{break-inside:auto}.db-level,.db-article h2,.db-topic h3{break-after:avoid}.db-eq,.db-x,.db-note{break-inside:avoid}.db-extra{break-inside:auto}}@media print{.db-level.ahl{break-before:page;margin-top:0}}@media print{.db-extra{break-inside:avoid}}@media screen and (max-width:760px){.db-tbl:not(.si) thead{display:none}.db-tbl:not(.si),.db-tbl:not(.si) tbody{display:block}.db-tbl:not(.si) tr{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:2px 10px;padding:10px 12px;border-top:1px solid var(--line)}.db-tbl:not(.si) tr:first-child{border-top:0}.db-tbl:not(.si) td{border:0;padding:0;min-width:0}.db-tbl:not(.si) td:first-child{min-width:0;font-weight:600}.db-tbl:not(.si) td:nth-child(3){grid-column:1/-1}}@media screen and (max-width:560px){.db-symbols{grid-template-columns:repeat(2,minmax(0,1fr))}}/* maths formula sheets */.fs-lab{margin:0 0 2px;font-size:13.5px;font-weight:600;color:var(--ink)}.fs-article .db-topic h3 small{display:inline-block;font:500 10.5px var(--mono);border-radius:999px;padding:2px 7px;vertical-align:middle;margin-left:4px}.fs-article .db-topic h3 small.sl{background:var(--tint);color:var(--ink-2)}.fs-article .db-topic h3 small.hl{background:var(--ink);color:var(--paper)}.fs-article .db-topic{grid-template-columns:minmax(120px,18%) minmax(0,1fr)}.fs-article .db-theme>.db-extra{margin-top:18px}@media print{.fs-lab{font-size:10.5px}.fs-article .db-topic{grid-template-columns:15% minmax(0,1fr)}}@media(max-width:760px){.fs-article .db-topic{grid-template-columns:minmax(0,1fr)}}/* chemistry: periodic table and not-retyped list */.pt-wrap,.opt-wrap{overflow-x:auto;position:relative}.pt{display:grid;grid-template-columns:repeat(18,minmax(38px,1fr));grid-template-rows:repeat(7,auto) 10px repeat(2,auto);gap:2px;min-width:720px}.pt .el{border:1px solid var(--line2);border-radius:4px;padding:2px 3px;text-align:center;background:var(--card);line-height:1.1}.pt .el small{display:block;font:500 9px var(--mono);color:var(--ink-2);text-align:left}.pt .el b{display:block;font:700 14px var(--head);color:var(--ink)}.pt .el span{display:block;font-size:9.5px;color:var(--ink-2)}.pt .el.fk{display:grid;place-items:center;font:500 9px var(--mono);color:var(--ink-2);background:var(--tint)}.db-nr{margin:0;padding-left:1.2em}.db-nr li{margin:.4em 0;color:var(--ink-2);font-size:14.5px}.db-nr b{color:var(--ink)}@media print{.pt{min-width:0;grid-template-columns:repeat(18,1fr)}.pt .el b{font-size:10px}.pt .el small,.pt .el span{font-size:6.5px}}/* one-page periodic table */.opt{display:grid;grid-template-columns:repeat(18,1fr);grid-template-rows:repeat(7,auto) 3px repeat(2,auto);gap:1px}.opt .el{border:.5px solid var(--line2);padding:0 1px;line-height:1.05;text-align:center}.opt .el small{display:block;font-size:4.6px;color:var(--ink-2);text-align:left}.opt .el b{display:block;font:700 7.4px var(--head)}.opt .el span{display:block;font-size:4.6px;color:var(--ink-2)}.opt .el.fk{font-size:4.6px;color:var(--ink-2);display:grid;place-items:center}.op-span{column-span:all;margin:0 0 4px}/* sticky section chips + back-to-top (lean sweep) */.db-toc{position:sticky;top:60px;z-index:20;background:color-mix(in srgb,var(--bg) 94%,transparent);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);padding:8px 0;margin:0 0 14px;overflow-x:auto;scrollbar-width:none}.db-toc::-webkit-scrollbar{display:none}.db-toc ul{flex-wrap:nowrap;margin:0}.db-toc a{white-space:nowrap}.db-top{text-align:center;margin:20px 0 0}.db-top a{display:inline-block;border:1px solid var(--edge);border-radius:999px;padding:8px 16px;font-weight:600;text-decoration:none}@media print{.db-top{display:none}}/* IB grade calculator (/tools/ib-grade-calculator/) */.gc-hero{padding-bottom:20px}.gc-hero h1{font-size:clamp(34px,4.6vw,58px);max-width:20ch}.gc-sec{padding-top:30px}.gc-grid{display:grid;gap:22px;align-items:start}@media(min-width:960px){.gc-grid{grid-template-columns:minmax(0,1.35fr) minmax(0,.9fr)}.gc-out{position:sticky;top:90px}}.gc-form h2{font-size:clamp(24px,2.6vw,30px)}.gc-rows{display:grid;gap:10px;margin:18px 0 24px}.gc-row{display:grid;grid-template-columns:minmax(0,1fr) auto auto;gap:10px;align-items:center;padding:10px 0;border-bottom:1px solid var(--line)}.gc-name{font:600 15.5px var(--head);letter-spacing:-.02em;min-width:0}@media(max-width:560px){.gc-row{grid-template-columns:1fr auto}.gc-name{grid-column:1/-1}.gc-lvl{justify-self:start}.gc-cas{grid-column:1/-1}}.gc-lvl{display:inline-flex;border:1.5px solid var(--ink);border-radius:999px;overflow:hidden}.gc-lvl label{position:relative;cursor:pointer}.gc-lvl input{position:absolute;opacity:0;inset:0;margin:0;cursor:pointer}.gc-lvl span{display:block;font:500 14px var(--mono);padding:10px 16px;min-width:56px;text-align:center;color:var(--ink)}.gc-lvl input:checked+span{background:var(--ink);color:var(--on-navy)}.gc-lvl input:focus-visible+span{outline:2px solid var(--coral);outline-offset:-4px;border-radius:999px}.gc-sel{display:grid;gap:4px;font-size:14px;color:var(--ink-2)}.gc-sel select{appearance:none;-webkit-appearance:none;font:700 18px var(--head);color:var(--ink);background:#fff url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%23b8341a' stroke-width='2'/%3E%3C/svg%3E") no-repeat right 12px center;border:1.5px solid var(--line2);border-radius:12px;padding:9px 34px 9px 14px;min-height:46px;min-width:78px}.gc-sel select:focus-visible{outline:2px solid var(--coral);outline-offset:2px}.gc-core-h{margin-top:4px}.gc-core{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:14px;align-items:end}.gc-cas{display:flex;gap:10px;align-items:center;min-height:46px;font-weight:600;cursor:pointer}.gc-cas input{width:22px;height:22px;accent-color:var(--coral-ink);margin:0}.gc-actions{margin-top:22px}.gc-out{background:var(--desk-3);border:1px solid var(--edge);border-left:4px solid var(--dim);border-radius:20px;padding:clamp(22px,3vw,30px);min-width:0}.gc-out.pass{border-left-color:var(--mint)}.gc-out.fail{border-left-color:var(--coral)}.gc-big{margin:0;display:flex;align-items:baseline;gap:10px}.gc-big b{font:800 clamp(64px,9vw,96px)/1 var(--head);letter-spacing:-.05em;color:var(--lamp)}.gc-big span{font:500 20px var(--mono);color:var(--dim)}.gc-status{font:700 20px var(--head);letter-spacing:-.02em;margin:14px 0 8px}.gc-out.pass .gc-status{color:var(--ok-t)}.gc-out.fail .gc-status{color:var(--bad-t)}.gc-why{margin:0 0 18px;padding-left:18px;color:var(--dim);font-size:15px}.gc-why li{margin-bottom:6px}.gc-break{list-style:none;margin:0;padding:14px 0 0;border-top:1px solid var(--edge);display:grid;gap:8px}.gc-break li{display:flex;justify-content:space-between;gap:12px;font-size:15px;color:var(--dim)}.gc-break b{font:500 15px var(--mono);color:var(--text)}.gc-matrix{background:var(--paper);color:var(--ink);border-radius:18px;padding:8px;box-shadow:var(--sh1);max-width:520px}.gc-matrix table{width:100%;border-collapse:collapse;table-layout:fixed}.gc-matrix th,.gc-matrix td{text-align:center;padding:10px 2px;font:500 14px var(--mono);border-bottom:1px solid var(--line)}.gc-matrix thead th{font-size:12px;color:var(--ink-2)}.gc-matrix tbody th{font-size:12px;color:var(--ink-2);text-align:left;padding-left:8px}.gc-matrix td{font:700 18px var(--head)}.gc-matrix td.x{font:500 12px var(--mono);color:var(--coral-ink)}.gc-matrix td.on{background:var(--hl);border-radius:8px;outline:2px solid var(--ink)}.gc-matrix tbody tr:last-child>*{border-bottom:0}.gc-list{margin:0 0 18px;padding-left:20px;display:grid;gap:10px}.gc-list b{display:block;font:600 15px var(--head);color:var(--text)}.gc-list li{color:var(--dim)}.gc-more{margin-top:26px}/* mobile sticky result bar */.gc-bar{display:none}@media(max-width:959px){.gc-bar{display:flex;align-items:baseline;gap:8px;position:fixed;left:0;right:0;bottom:0;z-index:40;padding:12px max(16px,env(safe-area-inset-left)) calc(12px + env(safe-area-inset-bottom,0px));background:var(--frame);color:var(--frame-ink);text-decoration:none;box-shadow:0 -4px 16px rgba(0,0,0,.18)}.gc-bar b{font:800 26px/1 var(--head)}.gc-bar span{font:600 14px var(--body);opacity:.8}.gc-bar em{font:600 14px var(--body);font-style:normal;flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.gc-bar i{font:600 13px var(--body);font-style:normal;opacity:.85}.gc-bar.pass em:before{content:"\2713 "}.gc-bar.fail{background:#7a2330}body:has(.gc-bar) footer.site{padding-bottom:84px}}/* Home: IA & EE Coach highlight (tools/home_coach.py). Option A = product row with a sample report card;option B = navy band after the numbers strip. Navy-frame tokens from zz-navy-frame.css. */@font-face{font-family:"Caveat";src:url(/fonts/caveat.woff2) format("woff2");font-display:swap}:root{--hpen:#d23a2c}:root[data-theme="dark"]{--hpen:#ff8a7a}.hco-wrap{position:relative;max-width:520px;margin:0 auto;padding:10px 0 18px}.hco-card{background:var(--card);border:1px solid var(--band-line);border-radius:14px;box-shadow:0 1px 2px rgba(27,42,74,.06),0 18px 40px rgba(27,42,74,.14);overflow:hidden;transform:rotate(-.6deg);text-align:left}.hco-h{display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap;background:var(--band);border-bottom:1px solid var(--band-line);box-shadow:inset 4px 0 0 var(--frame);padding:12px 18px 12px 20px}.hco-t{font:700 11.5px var(--body);letter-spacing:.1em;text-transform:uppercase;color:var(--frame)}:root[data-theme="dark"] .hco-t{color:var(--frame-ink)}.hco-bd{font:700 12px var(--body);color:var(--ok-t,#2f7d4f);background:var(--ok-bg,#eaf6ee);border:1px solid var(--ok-b,#bfe0cb);border-radius:999px;padding:3px 10px}.hco-b{padding:16px 20px 16px}.hco-ti{font:800 22px/1.15 var(--head);letter-spacing:-.02em;margin:0 0 6px;color:var(--ink)}.hco-rq{font:italic 500 15px/1.45 var(--serif);color:var(--ink);border-left:3px solid var(--hpen);padding:1px 0 1px 12px;margin:8px 0 14px}.hco-s{font:700 14px var(--body);margin:0 0 4px;color:var(--ink)}.hco-pen{font:700 20px "Caveat",cursive;color:var(--hpen);margin-left:6px}.hco-pr{list-style:none;margin:0;padding:0;counter-reset:p}.hco-pr li{counter-increment:p;display:grid;grid-template-columns:34px 1fr;gap:10px;align-items:start;padding:10px 0;border-bottom:1px dashed var(--band-line)}.hco-pr li:before{content:counter(p);width:30px;height:30px;display:grid;place-items:center;font:700 24px "Caveat",cursive;color:var(--hpen);border:2px solid var(--hpen);border-radius:50%;transform:rotate(-6deg)}.hco-pr b{display:block;font:700 14.5px/1.3 var(--head);color:var(--ink)}.hco-m{display:flex;gap:6px;margin-top:5px;flex-wrap:wrap}.hco-m i{font:600 11px var(--body);font-style:normal;border:1px solid var(--band-line);background:var(--band);border-radius:999px;padding:2px 8px;color:var(--dim)}.hco-c{position:relative;white-space:nowrap}.hco-c:after{content:"";position:absolute;inset:-.25em -.3em -.2em -.3em;pointer-events:none;border:2px solid var(--hpen);border-radius:50%/60%;transform:rotate(-2deg)}.hco-ft{display:flex;align-items:center;gap:12px;margin-top:14px;padding-top:12px;border-top:2px solid var(--hpen);flex-wrap:wrap}.hco-stamp{font:700 18px "Caveat",cursive;color:var(--hpen);border:2px solid var(--hpen);border-radius:8px;padding:0 9px;transform:rotate(-4deg);line-height:1.3}.hco-n{font-size:12.5px;color:var(--dim)}/* option B: a navy highlight band */.hcb{background:var(--frame);color:var(--frame-ink);border-block:3px solid var(--gold,#a9742a)}.hcbw{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,1.1fr) auto;gap:20px 34px;align-items:center;padding-top:26px;padding-bottom:26px}.hcb-l h2{margin:6px 0 4px;font-size:clamp(22px,2.4vw,30px);color:var(--frame-ink)!important;letter-spacing:-.02em}.hcb-l p{margin:0;opacity:.88;font-size:15.5px;max-width:32em}.hcb-new{display:inline-block;font:700 11px var(--body);letter-spacing:.12em;text-transform:uppercase;background:#f2d38b;color:#1b2a4a;border-radius:999px;padding:3px 10px}.hcb-q{margin:0 0 8px;font:700 13px var(--body);letter-spacing:.06em;text-transform:uppercase;opacity:.8}.hcb-chips{display:flex;flex-wrap:wrap;gap:8px}.hcb-chips a{color:inherit;text-decoration:none;font:600 14px var(--body);border:1px solid rgba(255,255,255,.35);border-radius:999px;padding:7px 14px;background:rgba(255,255,255,.07)}.hcb-chips a:hover{background:rgba(255,255,255,.18);border-color:#f2d38b}.hcb-r{display:flex;gap:10px;flex-wrap:wrap}.hcb .btn.primary{background:#fff;color:#1b2a4a;border-color:#fff}.hcb .btn.ghost{background:transparent;color:inherit;border-color:rgba(255,255,255,.5)}@media(max-width:1000px){.hcbw{grid-template-columns:1fr}}/* Home hero (option B, owner pick 2026-10-21): headline, course search, five illustrated subject tiles, drifting notation.Markup in tools/build.py home(); tile art in HERO_ART. Everything below the hero is unchanged. */.hhx{position:relative;overflow:hidden;padding:clamp(44px,7vw,96px) 0 clamp(40px,6vw,72px);text-align:center}.hgl{position:absolute;inset:0;pointer-events:none}.hgl span{position:absolute;font:600 22px var(--serif);font-style:italic;color:var(--ink);opacity:.07;animation:hh-drift 22s linear infinite;white-space:nowrap}@keyframes hh-drift{0%{transform:translateY(30px) rotate(-6deg)}50%{transform:translateY(-30px) rotate(6deg)}100%{transform:translateY(30px) rotate(-6deg)}}.hhb{position:relative}.hhb h1{font:800 clamp(40px,6.4vw,80px)/1.02 var(--head);letter-spacing:-.03em;margin:12px auto 16px;max-width:14em;color:var(--ink)}.hhb h1 em{font-style:normal;color:var(--gold);position:relative}.hhb .lede{margin:0 auto;max-width:36em;font-size:clamp(17px,1.6vw,19px);color:var(--ink-2)}.hhb .h2s{margin:26px auto 0;max-width:560px}.hcts{display:grid;gap:14px;margin:34px auto 0;max-width:1120px;grid-template-columns:repeat(5,1fr)}.hct{--c:var(--lv-c);position:relative;background:var(--card);border:1px solid var(--line);border-radius:18px;box-shadow:var(--sh1);padding:18px 16px 16px;text-align:left;display:flex;flex-direction:column;gap:4px;transition:transform .25s,box-shadow .25s;animation:hh-rise .6s both}.hct:nth-child(2){animation-delay:.08s}.hct:nth-child(3){animation-delay:.16s}.hct:nth-child(4){animation-delay:.24s}.hct:nth-child(5){animation-delay:.32s}@keyframes hh-rise{from{transform:translateY(16px)}}.hct:hover{transform:translateY(-4px);box-shadow:var(--sh2)}.hct:before{content:"";position:absolute;left:16px;right:16px;top:0;height:4px;border-radius:0 0 4px 4px;background:var(--c)}.hcart{width:100%;height:auto;aspect-ratio:200/120;color:var(--c);margin:6px 0 12px;background:linear-gradient(160deg,color-mix(in srgb,var(--c) 13%,transparent),color-mix(in srgb,var(--c) 4%,transparent));border-radius:14px;overflow:visible}.hcart .ax{fill:none;stroke:var(--line3);stroke-width:1.6;stroke-linecap:round}.hcart .ln{fill:none;stroke:currentColor;stroke-width:3.2;stroke-linecap:round;stroke-linejoin:round}.hcart .ln.alt{opacity:.55}.hcart .dash{stroke-dasharray:3 7;stroke-width:2.6}.hcart .fillc{fill:currentColor;opacity:.22}.hcart .fillc.soft{opacity:.12}.hcart .gl2{fill:none;stroke:var(--gold);stroke-width:2.4;stroke-linecap:round}.hcart .vec{fill:none;stroke:var(--ink);stroke-width:2.4;stroke-linecap:round}.hcart .pt{fill:var(--gold);stroke:var(--card);stroke-width:2}.hcart .dot{fill:currentColor;animation:hh-dp 3s ease-in-out infinite}@keyframes hh-dp{0%,100%{transform:none}50%{transform:translateY(-3px)}}.hcart .lab{font:italic 600 13px var(--serif);fill:var(--ink-2)}.hcart .lab.sm{font-size:11px}/* tangent rides the curve: the point stays on f(x) and the line turns with the slope */.hcart .tan{offset-path:path("M36 96 C60 56 80 36 108 44 S150 112 182 30");offset-rotate:auto;offset-distance:22%;animation:hh-tan 6s ease-in-out infinite alternate}@keyframes hh-tan{from{offset-distance:22%}to{offset-distance:82%}}.hcart .draw{stroke-dasharray:170;animation:hh-dr 4s ease-in-out infinite}@keyframes hh-dr{0%{stroke-dashoffset:170}45%,100%{stroke-dashoffset:0}}.hcart .ball{offset-path:path("M26 102 Q100 -14 176 102");animation:hh-fly2 3.2s cubic-bezier(.45,.05,.55,.95) infinite}@keyframes hh-fly2{0%{offset-distance:0%}100%{offset-distance:100%}}.hcart .bub{fill:var(--card);opacity:.9;animation:hh-bub 2.6s ease-in infinite}@keyframes hh-bub{0%{transform:none;opacity:0}20%{opacity:.9}100%{transform:translateY(-22px);opacity:0}}.hcart .bond{stroke:var(--line3);stroke-width:4;stroke-linecap:round}.hcart .atom.c{fill:var(--ink)}.hcart .atom.o{fill:currentColor}.hcart .atom.h{fill:var(--card);stroke:var(--line3);stroke-width:2}.hcart .spin{animation:hh-wob 6s ease-in-out infinite}@keyframes hh-wob{0%,100%{transform:rotate(-8deg)}50%{transform:rotate(8deg)}}.hcart .rung{stroke-width:3.4;stroke-linecap:round}.hcart .r0{stroke:var(--lv-f)}.hcart .r1{stroke:var(--lv-c)}.hcart .r2{stroke:var(--gold)}.hcart .r3{stroke:var(--bd3)}.hcart .helix{animation:hh-hx 4s ease-in-out infinite;transform-origin:70px 60px}@keyframes hh-hx{0%,100%{transform:scaleY(1)}50%{transform:scaleY(.82)}}.hcart .nuc{fill:currentColor;opacity:.35}.hcart .org{fill:var(--gold);opacity:.7}.hct b{font:800 19px var(--head);color:var(--ink)}.hct .hcn{font-size:13px;color:var(--mute)}.hcl{display:flex;gap:8px;margin-top:10px}.hcl a{flex:1;text-align:center;border-radius:10px;padding:9px 0;font:700 14px var(--body);border:1px solid var(--line2);color:var(--ink);text-decoration:none}.hcl a:first-child{background:var(--c);border-color:var(--c);color:var(--on-navy)}.hcl a:hover{filter:brightness(1.08)}.hhb .trust{justify-content:center;margin-top:26px}.hhb .h2c{display:none}.hct[hidden]{display:none}@media(max-width:1020px){.hcts{grid-template-columns:repeat(3,1fr)}}@media(max-width:640px){.hcts{grid-template-columns:1fr 1fr}.hct:last-child{grid-column:1/-1}.hct:last-child .hcart{max-height:130px}}@media(prefers-reduced-motion:reduce){.hhx *,.hcart *{animation:none!important;transition:none!important}}.hcart-l{display:block;border-radius:14px}.hcart-l:focus-visible{outline:2px solid var(--focus);outline-offset:2px}/* Home sections (tools/home_sections.py): practice demo (.px*), 'Written, not reworded' band (.ob*), feature explorer (.fx*). */.mv{font-family:"Iowan Old Style","Palatino Linotype",Georgia,serif;font-style:italic}.pxs-sec{padding:clamp(48px,7vw,96px) 0;background:linear-gradient(180deg,color-mix(in srgb,var(--lv-c) 9%,var(--bg)),var(--bg))}.pxh2{font:800 clamp(30px,4vw,46px)/1.1 var(--head);letter-spacing:-.02em;text-align:center;margin:8px 0 14px;color:var(--ink)}.pxlede{max-width:46em;margin:0 auto;text-align:center;color:var(--ink-2);font-size:17px}.pxtabs{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin:30px 0 26px}.pxtabs button{height:48px;padding:0 26px;border-radius:12px;border:0;background:var(--card);box-shadow:0 0 0 1px var(--line);font:700 15px var(--body);color:var(--ink-2);cursor:pointer;transition:.2s}.pxtabs button[aria-selected=true]{background:var(--btn2);color:var(--on-navy);box-shadow:var(--sh2)}.pxwin{display:grid;grid-template-columns:1fr 290px;background:var(--card);border:1px solid var(--line);border-radius:20px;box-shadow:var(--sh2);overflow:hidden;max-width:1120px;margin:0 auto}.pxmain{min-width:0}.pxh{display:flex;align-items:center;gap:14px;flex-wrap:wrap;padding:14px 22px;border-bottom:1px solid var(--line)}.pxt{font:700 11.5px var(--body);letter-spacing:.08em;text-transform:uppercase;color:var(--lv-c);background:color-mix(in srgb,var(--lv-c) 12%,transparent);padding:6px 10px;border-radius:7px}.pxl{font:700 13px var(--body);color:var(--lc);display:inline-flex;align-items:center;gap:8px}.pxd{display:inline-flex;gap:4px}.pxd i{width:8px;height:8px;border-radius:50%;background:var(--line2)}.pxd i.on{background:var(--lc)}.pxc{margin-left:auto;font-size:13px;color:var(--mute)}.pxb{padding:22px 24px 26px;font-family:"Iowan Old Style","Palatino Linotype",Georgia,"Times New Roman",serif;font-size:18.5px;line-height:1.6;color:var(--ink)}.pxmm{margin:0 0 10px;color:var(--ink-2)}.pxs{margin:0 0 14px}.pxp{list-style:none;margin:0;padding:0;display:grid;gap:10px}.pxp li,.pxms li{display:grid;grid-template-columns:36px 1fr auto;gap:8px;align-items:baseline}.pxpm{color:var(--ink-2)}.pxms{margin-top:20px;border-top:1px dashed var(--line2);padding-top:14px;font-family:var(--body);font-size:15.5px}.pxmsh{font:700 11.5px var(--body);letter-spacing:.1em;text-transform:uppercase;color:var(--coral-ink);margin:0 0 10px}.pxms ol{list-style:none;margin:0;padding:0;display:grid;gap:8px}.pxms li{color:var(--ink-2);animation:pxin .4s both;animation-delay:var(--d)}.pxms li b{font:700 12px var(--body);color:var(--on-navy);background:var(--gold);border-radius:999px;padding:2px 9px}.pxms.step li{animation:none}.pxms.step li.h{visibility:hidden}@keyframes pxin{from{opacity:0;transform:translateX(-8px)}}.pxside{border-left:1px solid var(--line);padding:22px;display:flex;flex-direction:column;gap:10px;background:var(--desk-2)}.pxbtn{display:flex;align-items:center;gap:10px;width:100%;min-height:52px;padding:0 16px;border-radius:12px;border:0;background:color-mix(in srgb,var(--lv-c) 10%,var(--card));color:var(--ink);font:700 15px var(--body);cursor:pointer;text-align:left;flex-wrap:wrap}.pxbtn.pri{background:var(--btn2);color:var(--on-navy)}.pxbtn:hover{filter:brightness(1.05)}.pxbtn[aria-pressed=true]{box-shadow:0 0 0 2px var(--gold)}.pxtm{font-style:normal;font-weight:500;font-size:12.5px;color:var(--mute);margin-left:auto}.pxlink{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;color:var(--ink-2);font-size:14.5px;text-decoration:none;border-radius:10px}.pxlink:hover{background:var(--hov)}.pxlink:first-of-type{margin-top:auto}.pxfoot{text-align:center;margin:22px 0 0;color:var(--ink-2)}.pxfoot a{color:var(--coral-ink);font-weight:700}@media(max-width:860px){.pxwin{grid-template-columns:1fr}.pxside{border-left:0;border-top:1px solid var(--line);display:grid;grid-template-columns:1fr 1fr}.pxlink:first-of-type{margin-top:0}.pxc{margin-left:0;width:100%}}@media(max-width:520px){.pxside{grid-template-columns:1fr}.pxb{padding:18px;font-size:17px}.pxtabs button{padding:0 16px;height:42px}}.ob{padding:clamp(48px,7vw,90px) 0;background:var(--btn2);color:var(--on-navy)}.obw{display:grid;gap:clamp(28px,5vw,60px);align-items:center}@media(min-width:960px){.obw{grid-template-columns:1.15fr .85fr}}.ob .eyebrow{color:var(--gold)}:root[data-theme=dark] .ob .eyebrow{color:#8a5a14}.ob h2{font:800 clamp(28px,3.6vw,42px)/1.12 var(--head);letter-spacing:-.02em;margin:10px 0 16px;color:var(--on-navy)}.ob p{color:color-mix(in srgb,var(--on-navy) 80%,transparent);font-size:17px;line-height:1.65}.obt{list-style:none;padding:0;margin:26px 0 0;display:flex;flex-wrap:wrap;gap:12px}.obt li{flex:1 1 150px;border:1px solid color-mix(in srgb,var(--on-navy) 20%,transparent);border-radius:14px;padding:14px 16px}.obt b{display:block;font:800 22px var(--head);color:var(--gold)}:root[data-theme=dark] .obt b{color:#8a5a14}.obt span{font-size:13.5px;color:color-mix(in srgb,var(--on-navy) 75%,transparent)}.obq{margin:0 0 14px;background:color-mix(in srgb,var(--on-navy) 7%,transparent);border:1px solid color-mix(in srgb,var(--on-navy) 16%,transparent);border-radius:16px;padding:20px 22px}.obq blockquote{margin:0 0 10px;font:600 17px/1.5 var(--head);color:var(--on-navy)}.obq blockquote:before{content:"\201C";color:var(--gold);font-size:30px;line-height:0;vertical-align:-10px;margin-right:4px}.obq figcaption{font-size:13.5px;color:color-mix(in srgb,var(--on-navy) 70%,transparent)}.obby{font-size:14.5px!important}.ob a{color:var(--on-navy);text-decoration:underline;text-decoration-color:var(--gold);text-underline-offset:3px}@media(prefers-reduced-motion:reduce){.pxms li,.fxp,.fxlv i:after,.fxtp i:after,.fxbar i:after{animation:none}}/* Product slider (home_sections.slider): tabs + one scroll-snap track, navy frame, tallest slide sets the height. */.pst{padding:clamp(40px,6vw,72px) 0 clamp(24px,4vw,48px)}.pstabs{display:flex;justify-content:center;gap:8px;margin:24px auto 22px;overflow-x:auto;scrollbar-width:none;max-width:100%;padding:2px}.pstabs::-webkit-scrollbar{display:none}.pstabs button{flex:none;height:44px;padding:0 20px;border-radius:999px;border:0;background:var(--card);box-shadow:0 0 0 1px var(--line);font:700 14.5px var(--body);color:var(--ink-2);cursor:pointer;display:inline-flex;align-items:center;gap:9px;transition:.2s}.pstabs button:before{content:"";width:9px;height:9px;border-radius:3px;background:var(--dot)}.pstabs button:hover{box-shadow:0 0 0 1px var(--line3)}.pstabs button[aria-selected=true]{background:var(--btn2);color:var(--on-navy);box-shadow:var(--sh2)}.psf{position:relative;max-width:1104px;width:calc(100% - 44px);margin:0 auto;background:var(--card);border:1px solid var(--line);border-top:4px solid var(--frame);border-radius:var(--rl);box-shadow:var(--sh1);overflow:hidden}.psv{display:flex;overflow-x:auto;scroll-snap-type:x mandatory;scrollbar-width:none;overscroll-behavior-x:contain}.psv::-webkit-scrollbar{display:none}.pss{flex:0 0 100%;scroll-snap-align:start;display:grid;grid-template-columns:1fr 1fr;gap:48px;padding:44px 64px;min-width:0}.pss .hpt h3{font-size:clamp(26px,2.8vw,34px);font-weight:800;letter-spacing:-.03em;margin:0 0 20px;color:var(--ink)}.pss .hpt ul{margin-bottom:24px}.psa{position:absolute;top:50%;z-index:2;width:42px;height:42px;margin-top:-21px;border-radius:50%;border:1px solid var(--line2);background:var(--card);color:var(--ink);display:grid;place-items:center;cursor:pointer;box-shadow:var(--sh1)}.psa.prev{left:10px}.psa.next{right:10px}.psa:hover:not(:disabled){background:var(--btn2);color:var(--on-navy)}.psa:disabled{opacity:.3;cursor:default}.pstabs button{position:relative;overflow:hidden}.pstabs button.run:after{content:"";position:absolute;left:18px;bottom:6px;height:3px;width:0;border-radius:2px;background:var(--gold);animation:ps-fill 7s linear forwards}.pst.paused .pstabs button.run:after{animation-play-state:paused}@keyframes ps-fill{to{width:calc(100% - 36px)}}.psdots{display:flex;justify-content:center;gap:10px;margin:16px 0 0}.psdots button{width:10px;height:10px;padding:0;border-radius:99px;border:0;background:var(--line3);cursor:pointer;transition:width .25s,background .25s}.psdots button[aria-current=true]{width:28px;background:var(--btn2)}.psdots button:before{content:"";display:block;margin:-12px -6px;height:34px}.pslinks{text-align:center;margin:18px 0 0;font-size:14px;color:var(--mute)}.pslinks a{color:var(--ink);font-weight:600;text-decoration:none;border-bottom:1px solid var(--gold);margin:0 2px}@media(max-width:900px){.psf{width:calc(100% - 32px)}.pss{grid-template-columns:1fr;gap:20px;padding:24px 20px 28px;align-content:start}.pss .hpt{justify-content:flex-start}.psa{display:none}.pss .hpv{min-height:0;padding:14px;max-height:360px;overflow:hidden;-webkit-mask-image:linear-gradient(#000 82%,transparent);mask-image:linear-gradient(#000 82%,transparent)}.pstabs{justify-content:flex-start;margin-inline:-16px;padding-inline:16px}}/* home, e-books grid, learning app (2026-10-19 night): short, visual, a CTA in every block */nav.main>ul{gap:2px}nav.main>ul>li>a{display:flex;align-items:center;gap:6px;color:var(--dim);font-weight:500;font-size:15px;padding:8px 12px;border-radius:999px;text-decoration:none;white-space:nowrap}nav.main>ul>li>a:hover{color:var(--text);background:var(--hov)}nav.main>ul>li>a[aria-current]{background:var(--gold-t);color:var(--lamp)}.soon{font:500 10px var(--mono);text-transform:uppercase;letter-spacing:.06em;border:1px solid rgba(169,116,42,.5);color:var(--lamp);border-radius:999px;padding:1px 6px}/* ---- home (2026-10-20, approved mockup option-b3): hero panel, course picker, product rows with device frames ---- */.home{--dot:var(--gold)}.home .hw{max-width:1160px;padding-inline:max(22px,env(safe-area-inset-left,0px))}.home h1,.home h2{color:var(--ink)}.home em{font-family:var(--serif);font-style:italic;font-weight:600;color:var(--gold);letter-spacing:-.01em}.hh{padding:32px 0 8px}.hp{background:var(--desk-2);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh2);padding:72px 48px 48px;text-align:center}.hp h1{font-size:clamp(34px,4.8vw,56px);font-weight:800;letter-spacing:-.035em;max-width:16em;margin:0 auto;line-height:1.08;text-wrap:balance}.hp .lede{margin:20px auto 32px;text-align:center;font-size:18px;color:var(--dim)}.hp .ctas{justify-content:center}.trust{list-style:none;display:flex;flex-wrap:wrap;justify-content:center;margin:40px 0 0;padding:24px 0 0;border-top:1px solid var(--line);gap:8px 0}.trust li{padding:0 20px;font-size:13px;font-weight:600;color:var(--dim);border-left:1px solid var(--line2)}.trust li:first-child{border:0}/* hero option 2 (owner choice 2026-10-20): course search + chips, overlapping devices, numbers strip, how it works */.h2x .hp{padding:56px 40px 0;overflow:hidden}.h2x .hp h1{max-width:15em}.h2x .hp .lede{margin:18px auto 28px}.h2s{max-width:640px;margin:0 auto;text-align:left}.h2s label{position:relative;display:block}.h2s svg.si{position:absolute;left:16px;top:50%;margin-top:-8px;color:var(--mute)}.h2s input{width:100%;height:56px;border:0;border-radius:12px;background:var(--card);box-shadow:0 0 0 1px var(--line2),var(--sh2);padding:0 18px 0 46px;font:500 16px var(--body);color:var(--ink)}.h2s input::placeholder{color:var(--mute)}.h2s input:focus{outline:2px solid var(--focus);outline-offset:1px}.h2c{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin:16px auto 0;max-width:760px}.h2g{display:contents}.h2g[hidden]{display:none}.h2c a{display:inline-flex;align-items:center;gap:8px;height:40px;padding:0 16px;border-radius:10px;background:var(--card);box-shadow:0 0 0 1px var(--line3),0 1px 2px rgba(27,42,74,.06);font:600 14px var(--body);color:var(--ink);transition:.15s;text-decoration:none}.h2c a:hover{transform:translateY(-1px);box-shadow:0 0 0 1px var(--gold),0 6px 14px rgba(27,42,74,.1)}.h2c a i{font-style:normal;font-size:11px;font-weight:700;letter-spacing:.06em;padding:2px 6px;border-radius:5px;background:var(--tint);color:var(--dim)}.h2c a[hidden]{display:none}.h2n{font-size:13px;color:var(--mute);margin:12px 0 0;text-align:center}.h2x .trust{margin-top:28px;padding-top:0;border:0}.h2d{container-type:inline-size;position:relative;margin:36px auto 0;max-width:900px;padding:0 2%}.hsl{position:relative;aspect-ratio:900/540}.hs{position:absolute;inset:0;display:grid;place-items:center;opacity:0;visibility:hidden;transform:translateX(5%) scale(.97);transition:opacity .7s ease,transform .7s ease,visibility 0s .7s}.hs.on{opacity:1;visibility:visible;transform:none;transition-delay:0s}.hs.out{transform:translateX(-5%) scale(.97)}.hs .dev{margin:0;max-width:none}.hs .mac{width:80%}.hs .ipad.land{width:68%}.hs .ipad.port{width:40%}.hs .iph{width:25%;max-width:none;border-radius:min(32px,4cqw);padding:max(3px,.7cqw)}.hs .iph .sc{border-radius:min(26px,3.2cqw)}.hs .ipad{border-radius:min(18px,2.4cqw);padding:max(4px,.9cqw)}.hs .ipad .sc{border-radius:min(10px,1.4cqw)}.hsd{display:flex;justify-content:center;gap:2px;height:28px;margin-top:6px}.hsd button{width:24px;height:28px;padding:0;border:0;background:none;cursor:pointer;display:grid;place-items:center;border-radius:6px}.hsd button:before{content:"";width:8px;height:8px;border-radius:50%;background:var(--line3);transition:.25s}.hsd button:hover:before{background:var(--mute)}.hsd button[aria-selected=true]:before{width:22px;border-radius:4px;background:var(--gold)}.hsd button:focus-visible{outline:2px solid var(--gold);outline-offset:1px}/* scrolling screens: a tall page slides up inside the device (build.py sets --k = share of the image that is off-screen) */.sc.tall{position:relative}.dev .sc.tall img{position:absolute;left:0;top:0;width:100%;height:auto;object-fit:initial;will-change:transform;animation:hscroll var(--d,18s) infinite;animation-play-state:paused}.sc.tall.run img{animation-play-state:running}.dev:hover .sc.tall.run img{animation-play-state:paused}@keyframes hscroll{0%,6%{transform:translateY(0);animation-timing-function:cubic-bezier(.45,0,.25,1)}52%,62%{transform:translateY(calc(var(--k) * -100%));animation-timing-function:cubic-bezier(.5,0,.2,1)}82%,100%{transform:translateY(0)}}@media(prefers-reduced-motion:reduce){.hs{transition:none}.dev .sc.tall img{animation:none;transform:none}}.xnstrip{padding:24px 0 0}.xns{list-style:none;margin:0 auto;padding:0;max-width:1104px;width:calc(100% - 44px);display:grid;grid-template-columns:repeat(4,1fr);background:var(--card);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1)}.xns li{padding:28px 20px;text-align:center;border-left:1px solid var(--line)}.xns li:first-child{border:0}.xns b{display:block;font:800 clamp(30px,4vw,46px)/1 var(--head);letter-spacing:-.03em;color:var(--ink)}.xns span{display:block;margin-top:8px;font-size:13px;font-weight:600;color:var(--dim)}.xhow{padding:40px 0 16px}.xhow .eyebrow{text-align:center;margin-bottom:20px}.xsteps{list-style:none;margin:0 auto;padding:0;max-width:1104px;width:calc(100% - 44px);display:grid;grid-template-columns:repeat(3,1fr);gap:24px}.xsteps li{position:relative;background:var(--card);border:1px solid var(--line);border-radius:var(--rs);box-shadow:var(--sh1);padding:24px 24px 26px}.xsteps li:not(:last-child):after{content:"→";position:absolute;right:-19px;top:50%;margin-top:-12px;width:14px;color:var(--gold);font-weight:700;z-index:1}.xsteps .xico{display:grid;place-items:center;width:48px;height:48px;border-radius:12px;background:var(--tint);color:var(--ink);border:1px solid var(--line);margin-bottom:16px}.xsteps .xsn{position:absolute;top:24px;right:24px;font:700 12px var(--body);letter-spacing:.14em;color:var(--mute)}.xsteps h3{font:800 18px/1.25 var(--head);letter-spacing:-.02em;margin:0 0 6px;color:var(--ink)}.xsteps p{margin:0;color:var(--dim);font-size:14.5px}@media(max-width:900px){.xns{grid-template-columns:1fr 1fr;width:calc(100% - 32px)}.xns li:nth-child(3){border-left:0}.xns li:nth-child(n+3){border-top:1px solid var(--line)}.xns li{padding:20px 12px}.xsteps{grid-template-columns:1fr;width:calc(100% - 32px);gap:16px}.xsteps li:not(:last-child):after{display:none}.h2x .hp{padding:40px 22px 0}}@media(max-width:640px){.h2x .hp{padding:32px 16px 0}.h2x .hp .lede{margin:14px auto 20px;font-size:16px}.h2s input{height:50px;font-size:15px}.h2c{display:grid;grid-template-columns:1fr 1fr;gap:8px}.h2g{display:flex;align-items:center;gap:4px;min-width:0;height:44px;padding:0 5px 0 10px;border-radius:10px;background:var(--card);box-shadow:0 0 0 1px var(--line3),0 1px 2px rgba(27,42,74,.06)}.h2g:before{content:attr(data-name);flex:1;min-width:0;font:600 13px var(--body);color:var(--ink);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.h2c .h2g a{height:30px;padding:0 7px;box-shadow:none;background:var(--tint);border-radius:7px;font-size:12px;gap:0}.h2c .h2g a .gn{display:none}.h2c .h2g a i{background:none;padding:0;font-size:12px;color:var(--ink)}.h2c .h2g a:hover{transform:none;box-shadow:0 0 0 1px var(--gold)}.h2x .trust{display:grid;grid-template-columns:auto auto;justify-content:center;gap:4px 0;margin-top:20px}.h2x .trust li{border:0;padding:0;font-size:12.5px;white-space:nowrap}.h2x .trust li:nth-child(odd):after{content:"·";margin:0 8px;color:var(--mute)}.h2x .trust li:nth-child(even){text-align:left}.h2d{margin-top:22px;padding:0}.hsl{aspect-ratio:1/1.04}.hs .mac,.hs .ipad.land{width:100%}.hs .ipad.port{width:62%}.hs .iph{width:45%;border-radius:30px;padding:6px}.hs .iph .sc{border-radius:25px}.hs .ipad{border-radius:14px;padding:6px}.hs .ipad .sc{border-radius:8px}.xnstrip{padding-top:16px}.xns li{padding:14px 8px}.xns b{font-size:28px}.xns span{font-size:12px;margin-top:4px}.xhow{padding-top:28px}.xsteps{gap:10px}.xsteps li{display:grid;grid-template-columns:44px 1fr;gap:0 14px;align-items:center;padding:14px 16px}.xsteps .xico{grid-row:1/3;width:44px;height:44px;margin:0}.xsteps .xsn{display:none}.xsteps h3{font-size:15.5px;margin:0 0 2px}.xsteps p{font-size:13.5px;line-height:1.4}}.hprs{padding:12px 0}.home .hrow{display:grid;grid-template-columns:1fr 1fr;gap:56px;align-items:stretch;background:var(--card);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1);padding:48px;max-width:1104px;width:calc(100% - 44px);margin-inline:auto}.hrow.flip .hpt{order:2}.hpt{display:flex;flex-direction:column;justify-content:center;align-items:flex-start;min-width:0}.hpt h2{font-size:clamp(26px,2.8vw,34px);font-weight:800;letter-spacing:-.03em;margin-bottom:20px}.hpt .eyebrow{display:flex;align-items:center;gap:8px;margin-bottom:12px;font-size:11.5px}.hpt .eyebrow:before{content:"";width:8px;height:8px;border-radius:2px;background:var(--dot)}.hpt ul{list-style:none;padding:0;margin:0 0 28px;width:100%;color:var(--dim)}.hpt li{padding:12px 0 12px 28px;position:relative;font-size:15.5px;border-top:1px solid var(--line)}.hpt li:last-child{border-bottom:1px solid var(--line)}.hpt li:before{content:"";position:absolute;left:2px;top:19px;width:12px;height:8px;border-left:2px solid var(--dot);border-bottom:2px solid var(--dot);transform:rotate(-45deg) scale(.8)}.hpt li b{color:var(--ink)}.home .ctas{align-items:center;gap:12px;margin:0}.unl{font-size:13px;color:var(--mute);margin:20px 0 0;display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center}.unl a{color:var(--ink);font-weight:600;border-bottom:1px solid var(--gold);text-decoration:none}.hpv{background:var(--tint);border:1px solid var(--line);border-radius:var(--rs);padding:24px;display:grid;place-items:center;min-height:380px;min-width:0}/* device frames: CSS only, screenshots inside */.dev{position:relative;width:100%;margin:0 auto}.dev img{display:block;width:100%;height:100%;object-fit:cover;object-position:top left}.mac{max-width:520px}.mac .bz{background:#17171a;border-radius:12px 12px 4px 4px;padding:2.4% 2.4% 3.2%;position:relative;box-shadow:inset 0 0 0 1px #3a3a40,0 2px 4px rgba(27,42,74,.15),0 24px 40px -8px rgba(27,42,74,.28)}.mac .bz:before{content:"";position:absolute;top:1.1%;left:50%;width:5px;height:5px;margin-left:-2.5px;border-radius:50%;background:#2c2c32;box-shadow:inset 0 0 0 1px #3d3d44}.mac .sc{aspect-ratio:16/10;border-radius:3px;overflow:hidden;background:#fff}.mac .bs{height:12px;margin:0 -4.5%;border-radius:0 0 14px 14px;background:linear-gradient(#e4e6ea,#b8bbc2 70%,#9da1a9);position:relative;box-shadow:0 14px 22px -6px rgba(27,42,74,.3)}.mac .bs:before{content:"";position:absolute;left:50%;top:0;width:18%;height:5px;margin-left:-9%;background:linear-gradient(#a7aab2,#cfd2d8);border-radius:0 0 8px 8px}.ipad{background:#17171a;border-radius:20px;padding:9px;box-shadow:inset 0 0 0 1px #3a3a40,0 2px 4px rgba(27,42,74,.15),0 24px 40px -8px rgba(27,42,74,.28)}.ipad .sc{border-radius:12px;overflow:hidden;background:#fff}.ipad.land{max-width:480px}.ipad.land .sc{aspect-ratio:1180/820}.ipad.port{max-width:330px}.ipad.port .sc{aspect-ratio:3/4}.ipad.port .sc img{object-position:top center}.iph{background:#17171a;border-radius:38px;padding:7px;box-shadow:inset 0 0 0 1px #3a3a40,0 2px 4px rgba(27,42,74,.15),0 20px 34px -8px rgba(27,42,74,.35);width:100%;max-width:230px;position:relative}.iph .sc{aspect-ratio:390/844;border-radius:31px;overflow:hidden;background:#fff;position:relative}.iph .sc:after{content:"";position:absolute;top:2.6%;left:50%;width:30%;height:3.3%;margin-left:-15%;background:#0a0a0c;border-radius:20px}.iph:before{content:"";position:absolute;right:-2px;top:22%;width:2px;height:12%;background:#2d2d33;border-radius:0 2px 2px 0}.iph:after{content:"";position:absolute;left:-2px;top:18%;width:2px;height:7%;background:#2d2d33;border-radius:2px 0 0 2px;box-shadow:0 36px 0 #2d2d33}.iph .sc svg{display:block;width:100%;height:100%}.combo{position:relative;width:100%;max-width:520px;margin:0 auto;padding-bottom:6%}.combo .iph{position:absolute;right:-3%;bottom:0;width:23%;border-radius:22px;padding:4px}.combo .iph .sc{border-radius:18px}.combo .iph:before,.combo .iph:after{display:none}.hq{padding:56px 0 24px}.htwo{display:grid;grid-template-columns:.7fr 1.3fr;gap:48px}.hq h2{font-size:clamp(26px,3vw,34px);font-weight:800;letter-spacing:-.03em}.faqw{background:var(--card);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1);padding:0 24px}.faqw details{background:none;border:0;border-radius:0;box-shadow:none;border-top:1px solid var(--line);padding:0;margin:0}.faqw details:first-child{border-top:0}.faqw summary{padding:20px 0;font:600 17px var(--body);letter-spacing:0;color:var(--ink)}.faqw summary:after{width:28px;height:28px;display:grid;place-items:center;background:var(--tint);border-radius:8px;font-size:18px;line-height:1;padding-bottom:2px;flex:none}.faqw p{margin:0 0 22px;color:var(--dim);max-width:46em}.hfin{padding:24px 0 64px}.fp{border-radius:var(--rl);padding:64px 32px;text-align:center;color:#fff;background-color:#1b2a4a;background-image:radial-gradient(circle at 12% 0%,rgba(169,116,42,.35),transparent 45%),radial-gradient(circle at 90% 100%,rgba(36,99,166,.35),transparent 50%);box-shadow:var(--sh2)}.fp h2{color:#fff;font-size:clamp(28px,3.6vw,42px);font-weight:800}.fp p{color:#cdd5e6;font-size:17px;margin:12px 0 28px}.fp .ctas{justify-content:center}.fp .btn.primary{background:#fff;color:#1b2a4a;box-shadow:0 6px 16px rgba(0,0,0,.2)}.fp .btn.ghost{background:transparent;color:#fff;box-shadow:0 0 0 1px rgba(255,255,255,.4)}@media(max-width:1000px){.combo .iph{right:0}}@media(max-width:900px){.home .hrow{grid-template-columns:1fr;gap:24px;padding:24px 20px;width:calc(100% - 32px)}.hrow.flip .hpt{order:0}.hpv{min-height:0;padding:16px}.hp{padding:48px 22px 32px}.htwo{grid-template-columns:1fr;gap:20px}.trust li{padding:0 12px}.mac,.combo{max-width:440px}.iph{max-width:190px}}@media(max-width:560px){.trust{gap:6px 0}.home .hp .ctas .btn,.home .hpt .ctas .btn{flex:1 1 100%}.home .ctas{width:100%}.hh{padding-top:16px}}.mock{background:var(--desk-3);border:1px solid var(--edge);border-radius:18px;padding:18px;box-shadow:var(--sh1);max-width:520px;width:100%}.mk-top{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-bottom:12px}.mk-top b{font:700 16px var(--head);margin-right:auto}.mock .chip{margin:0;font-size:11.5px;padding:2px 9px}.mock .chip.free{color:var(--ok-t);border-color:var(--ok-b)}.mk-lv{list-style:none;margin:0;padding:0;display:grid;gap:6px}.mk-lv li{display:grid;grid-template-columns:1fr 70px 70px;gap:8px;align-items:center;font-size:14px}.mk-lv li b{font:600 14px var(--head)}.mk-lv li span{background:var(--gold-t);color:var(--lamp);border-radius:8px;text-align:center;padding:6px 0;font:500 12px var(--mono)}.mk-lv li.hd span{background:none;color:var(--dim);padding:0}.mk-lv li.hd b{font:500 11.5px var(--mono);color:var(--dim);text-transform:uppercase}.mk-foot{margin-top:12px;color:var(--dim);font-size:13px}.mock svg{width:100%;height:auto;display:block}/* e-books page */.bgrid{grid-template-columns:repeat(auto-fill,minmax(min(100%,280px),1fr))}.book-card.bbuy{transform:none}.book-card.bbuy:hover{transform:translateY(-4px)}.bbuy .shelf{gap:0}.bbuy .shelf img{width:38%;max-width:130px}.bbuy .shelf.two img{width:34%}.bbuy .shelf.two img+img{margin-left:-6%}.bbuy .buys{display:flex;flex-wrap:wrap;gap:8px;margin-top:auto;position:relative;z-index:2}.bbuy .buys .btn{flex:1 1 auto;padding:10px 14px;font-size:14.5px}.bbuy .more{position:relative;z-index:2;font-size:14px;font-weight:700}.soonbar{max-width:720px}.lapp .card h3{margin-top:0}.lapp2{align-items:center;gap:32px}@media(max-width:700px){.mk-lv li{grid-template-columns:1fr 54px 54px}.hhero{padding-block:30px 18px}}@media(min-width:1221px) and (max-width:1500px){nav.main>ul>li>a{padding:8px 8px;font-size:14px}.hsrch span,.hsrch kbd,header.site .signin small{display:none}header.site .wrap{gap:8px}}/* Navy bands on the home page keep light text in light mode too (the .home h2 rule above made it navy on navy). */.home .ob h2,.home .hcb h2{color:var(--on-navy)}.home .ob .eyebrow,.home .ob .obt b{color:var(--gold)}/* Home H1: catchy line + a smaller keyword line inside the same H1 (SEO, owner 2026-10-21). */.home h1 .h1s{display:block;font:600 clamp(16px,1.9vw,21px)/1.35 var(--body);letter-spacing:0;color:var(--ink-2);margin-top:14px}.vh{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}.quick{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(200px,1fr))}.quick .q{display:grid;gap:4px;align-content:start;background:var(--desk-3);border:1px solid var(--edge);border-radius:16px;padding:16px;text-decoration:none;color:var(--text);transition:border-color .2s,transform .2s}.quick .q:hover{border-color:var(--lamp);transform:translateY(-2px)}.quick .q .eyebrow{margin:0}.quick .q b{font:700 17px var(--head);letter-spacing:-.02em}.quick .q span:last-child{font-size:14px;color:var(--dim)}.theme{margin:26px 0}.theme h3{font-size:clamp(19px,2vw,23px);margin:0 0 4px}.tintro{color:var(--dim);max-width:72ch;margin:0 0 12px}.topics{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(240px,1fr))}.topic{display:grid;gap:4px;background:var(--paper);color:var(--ink);border-radius:12px;padding:14px 16px;text-decoration:none;box-shadow:var(--sh1);transition:transform .2s}.topic:hover{transform:translateY(-3px)}.topic .tnum{font:500 11.5px var(--mono);color:var(--coral-ink);text-transform:uppercase}.topic b{font:700 16.5px var(--head);letter-spacing:-.02em}.topic .tdesc{font-size:14px;color:var(--ink-2);line-height:1.45}.imports .card{min-width:0}.imports .card h3{font-size:18px;margin-top:0}.imports .card table{width:100%;border-collapse:collapse;font-size:14px;display:block;overflow-x:auto}.imports .card th,.imports .card td{border-bottom:1px solid var(--line);padding:8px;text-align:left;vertical-align:top}.imports .card li{margin-bottom:8px}.faqwrap h2{margin-bottom:14px}.theme h2{font-size:clamp(22px,2.6vw,28px);margin:0 0 6px}.theme h2 small{font:500 12px var(--mono);color:var(--lamp);margin-left:8px;letter-spacing:0;vertical-align:middle}.slnote{margin:0 0 16px}.slnote h2{font-size:20px;margin:0 0 6px}/* predicted papers */.pp-status{border:1px solid var(--edge);border-left:4px solid var(--lamp);background:var(--desk-2);border-radius:12px;padding:14px 18px;margin:0 0 26px}.pp-status p{margin:0;color:var(--text)}.pp-status .eyebrow{color:var(--lamp);margin-bottom:4px}.pp-bars{list-style:none;margin:14px 0 10px;padding:0;display:grid;gap:8px}.pp-bars li{display:grid;grid-template-columns:minmax(0,1fr) 48px;grid-template-rows:auto 8px;gap:3px 10px;align-items:center}.pp-bars span{font-size:14px;color:var(--ink)}.pp-bars b{grid-row:1/3;grid-column:2;font:500 13px var(--mono);color:var(--ink);text-align:right}.pp-bars i{grid-column:1;height:8px;border-radius:4px;background:var(--coral)}@media(min-width:900px){.quick.pp-courses{grid-template-columns:repeat(3,minmax(0,1fr))}}.pp-how .card h3{font-size:clamp(19px,2vw,22px);margin:2px 0 8px}/* worksheet studio */.st-feat .card h3{margin:2px 0 6px}.st-shots{align-items:start}.st-shots figure,.st-wide{margin:0}.st-shots img,.st-wide img{width:100%;height:auto;border-radius:14px;border:1px solid var(--edge);box-shadow:var(--sh1);background:var(--card);display:block}.st-shots figure:last-child img{max-width:420px;margin:0 auto}.st-shots figcaption{font-size:13.5px;color:var(--dim);margin-top:10px;text-align:center}.st-wide{margin-bottom:18px}.st-tiers .ptable td:first-child{font-weight:600;white-space:nowrap}.st-legal{padding-block:0 30px}.schools-band{display:grid;grid-template-columns:minmax(0,1fr) 220px;gap:32px;align-items:center;background:var(--desk-2);border:1px solid var(--edge);border-radius:24px;padding:clamp(22px,4vw,40px);overflow:hidden}.schools-band h2{margin:4px 0 10px}.schools-band p{color:var(--dim)}.schools-band .eyebrow{color:var(--lamp)}.schools-band img{width:100%;height:auto;border-radius:8px;transform:rotate(3deg);box-shadow:var(--sh1)}@media(max-width:700px){.schools-band{grid-template-columns:minmax(0,1fr)}.schools-band img{max-width:180px;justify-self:center}}/* home: look inside */.tour-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}.tour-card{display:flex;flex-direction:column;gap:4px;text-decoration:none;color:var(--text);min-width:0}.tour-img{display:block;aspect-ratio:16/10;border-radius:12px;overflow:hidden;border:1px solid var(--edge);background:var(--desk-2);margin-bottom:8px;box-shadow:var(--sh1);transition:transform .25s,border-color .25s}.tour-img img{width:100%;height:100%;object-fit:cover;object-position:top left;display:block}.tour-card:hover .tour-img{transform:translateY(-3px);border-color:var(--lamp)}.tour-card .eyebrow{color:var(--lamp)}.tour-card b{font:600 15.5px/1.35 var(--head);color:var(--text)}@media(prefers-reduced-motion:reduce){.tour-img{transition:none}}@media(max-width:1000px){.tour-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:420px){.tour-grid{gap:12px}.tour-card b{font-size:14px}}/* cheatsheets hub, lean: course tabs, compact topic lists, no cards */.cs-tabs{display:flex;gap:6px;padding:5px;background:var(--band);border:1px solid var(--band-line);border-radius:14px;width:max-content;max-width:100%;overflow-x:auto;margin:0 0 18px}.cs-tabs[hidden]{display:none}.cs-tabs button{font:700 14.5px var(--body);color:var(--ink-2);background:none;border:0;border-radius:10px;padding:10px 16px;min-height:42px;cursor:pointer;white-space:nowrap}.cs-tabs button[aria-selected=true]{background:var(--frame);color:var(--frame-ink);box-shadow:var(--sh1)}.cs-panel{background:var(--card);border:1px solid var(--line);border-top:3px solid var(--frame);border-radius:var(--rl);padding:22px clamp(16px,3vw,28px) 10px;margin:0 0 20px}.cs-panel[hidden]{display:none}.cs-panel h2{font-size:clamp(22px,2.6vw,28px);margin:0 0 6px}.cs-panel h2 small{font:500 12px var(--mono);color:var(--lamp);margin-left:8px;letter-spacing:0;vertical-align:middle}.cs-cols{columns:3 250px;column-gap:28px;margin-top:8px}.cs-th{break-inside:avoid;margin:0 0 18px}.cs-th h3{font:700 12.5px var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--coral-ink);margin:0 0 6px;padding-bottom:5px;border-bottom:2px solid var(--frame)}.cs-th ul{list-style:none;margin:0;padding:0}.cs-th li{margin:0}.cs-th a{display:flex;gap:8px;align-items:baseline;justify-content:space-between;padding:7px 2px;border-bottom:1px solid var(--line);text-decoration:none;color:var(--ink);font:600 15px var(--head)}.cs-th a:after{content:"\2192";color:var(--coral-ink)}.cs-th a:hover{color:var(--coral-ink)}.cs-th .tnum{font:500 11px var(--mono);color:var(--mute);margin-right:6px;min-width:3ch}.cs-th a{justify-content:flex-start}.cs-th a:after{margin-left:auto}.cs-sl{color:var(--dim);margin:0}.cs-tiles{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.cs-tiles a{display:grid;gap:4px;align-content:start;text-decoration:none;color:var(--ink);padding:16px;border-radius:var(--rl);border:1px solid var(--line);border-left:4px solid var(--frame);background:var(--card);height:100%}.cs-tiles span[aria-hidden]{display:grid;place-items:center;width:38px;height:38px;border-radius:10px;background:var(--frame);color:var(--frame-ink);font:700 18px var(--head)}.cs-tiles h3{margin:6px 0 0;font-size:18px}.cs-tiles p{margin:0;font-size:14px;color:var(--dim)}@media(max-width:760px){.cs-tiles{grid-template-columns:1fr}.cs-cols{columns:1}}/* /ib-ia-and-ee-guide/ (tools/pages_ia_hub.py): quiet rows in one framed panel per section; navy top rule, pale blue bands. */.iah{max-width:920px;padding-bottom:70px}.iah-hero{padding:26px 0 8px}.iah-hero h1{font-size:clamp(34px,4.6vw,54px);margin:6px 0 14px;letter-spacing:-.03em;line-height:1.06}.iah-hero .lede{max-width:46em;color:var(--ink-2)}.iah-jump{display:flex;flex-wrap:wrap;gap:8px;margin-top:18px}.iah-jump a{font:600 14px var(--body);text-decoration:none;color:var(--frame);border:1px solid var(--band-line);background:var(--band);border-radius:999px;padding:10px 16px;min-height:44px;display:inline-flex;align-items:center;box-sizing:border-box}:root[data-theme="dark"] .iah-jump a{color:var(--frame-ink)}.iah-jump a:hover{border-color:var(--gold)}.iah-sec{margin-top:46px;scroll-margin-top:84px}.iah-sec>h2{font-size:clamp(24px,2.8vw,32px);margin:0 0 6px;letter-spacing:-.02em}.iah-sub{margin:0 0 16px;color:var(--dim);max-width:44em}.iah-panel{list-style:none;margin:0;padding:0;background:var(--card);border:1px solid var(--band-line);border-top:3px solid var(--frame);border-radius:12px;box-shadow:0 1px 2px rgba(27,42,74,.05),0 8px 20px rgba(27,42,74,.05)}.iah-row{display:grid;grid-template-columns:44px minmax(0,1fr);gap:16px;padding:20px 22px;border-top:1px solid var(--band-line)}.iah-row:first-child{border-top:0}.iah-ic{width:40px;height:40px;border-radius:10px;background:var(--gold-t);color:var(--lamp);display:flex;align-items:center;justify-content:center}.iah-ic svg{width:22px;height:22px}.iah-row h3{margin:0 0 2px;font-size:19px;letter-spacing:-.01em}.iah-row p{margin:0 0 6px;color:var(--dim);font-size:15px}.iah-links{display:flex;flex-wrap:wrap;gap:0 20px}.iah-links a{font:600 14.5px var(--body);color:var(--ink);text-decoration:underline;text-decoration-color:var(--band-line);text-decoration-thickness:2px;text-underline-offset:5px;padding:10px 0;min-height:44px;box-sizing:border-box;display:inline-flex;align-items:center;border-bottom:2px solid transparent}.iah-links a:hover{color:var(--lamp);text-decoration:underline;text-underline-offset:4px}.iah-coach{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:28px;background:var(--band);border:1px solid var(--band-line);border-top:3px solid var(--frame);border-radius:12px;padding:26px 26px}.iah-lead{margin:0 0 12px;font-size:17px;color:var(--ink)}.iah-ticks{list-style:none;margin:0 0 14px;padding:0}.iah-ticks li{position:relative;padding:5px 0 5px 24px;color:var(--ink-2);font-size:15px}.iah-ticks li:before{content:"";position:absolute;left:3px;top:11px;width:10px;height:6px;border:solid var(--ok-t,#2f7d4f);border-width:0 0 2px 2px;transform:rotate(-45deg)}.iah-steps{display:flex;flex-wrap:wrap;gap:6px;list-style:none;margin:0;padding:0;counter-reset:s}.iah-steps li{counter-increment:s;font:600 12.5px var(--body);color:var(--frame);background:var(--card);border:1px solid var(--band-line);border-radius:999px;padding:4px 10px}:root[data-theme="dark"] .iah-steps li{color:var(--frame-ink)}.iah-steps li:before{content:counter(s);display:inline-grid;place-items:center;width:18px;height:18px;margin-right:6px;border-radius:50%;background:var(--frame);color:var(--frame-ink);font-size:11px}.iah-buy{display:flex;flex-direction:column;gap:10px;align-items:stretch}.iah-buy .btn{justify-content:center}.iah-buyh{margin:0;font:700 14px var(--body);letter-spacing:.04em;text-transform:uppercase;color:var(--dim)}.iah-note{margin:2px 0 0;font-size:13.5px;color:var(--dim)}.iah-member{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;background:var(--card);border:1px solid var(--band-line);border-left:4px solid var(--gold);border-radius:12px;padding:20px 24px}.iah-member p{margin:0;color:var(--ink-2)}.iah-na{margin-top:46px;font-size:13px;color:var(--dim);border-top:1px solid var(--band-line);padding-top:14px}@media(max-width:760px){.iah-coach{grid-template-columns:1fr;padding:20px 18px}.iah-row{grid-template-columns:36px minmax(0,1fr);gap:12px;padding:16px 14px}.iah-ic{width:36px;height:36px}.iah-member{padding:16px}}.prose .ia-links{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:8px}.prose .ia-links a{display:inline-block;border:1px solid var(--band-line);background:var(--band);border-radius:999px;padding:10px 16px;text-decoration:none;color:var(--ink);font:600 14px var(--body);min-height:44px;box-sizing:border-box}.prose .ia-links a:hover{border-color:var(--gold)}.iah-row .btn{margin-top:8px}/* subject slider: scroll-snap cards with the home-hero art (tools/pages_ia_hub.py) */.iah-slider{position:relative}.iah-track{display:flex;gap:16px;overflow-x:auto;scroll-snap-type:x mandatory;-webkit-overflow-scrolling:touch;padding:6px 4px 16px;margin:0 -4px;scrollbar-width:none}.iah-track::-webkit-scrollbar{display:none}.iah-track:focus-visible{outline:2px solid var(--gold);outline-offset:2px;border-radius:12px}.iah-card{--c:var(--lv-c);flex:0 0 300px;scroll-snap-align:start;position:relative;display:flex;flex-direction:column;gap:6px;background:var(--card);border:1px solid var(--band-line);border-top:4px solid var(--frame);border-radius:14px;box-shadow:0 1px 2px rgba(27,42,74,.05),0 10px 24px rgba(27,42,74,.08);padding:16px 16px 18px;box-sizing:border-box}.iah-card:before{content:"";position:absolute;left:16px;right:16px;top:-4px;height:4px;border-radius:0 0 4px 4px;background:var(--c)}.iah-card .hcart{margin:2px 0 8px}.iah-card h3{margin:0;font-size:20px;letter-spacing:-.01em}.iah-card p{margin:0;color:var(--dim);font-size:14.5px;min-height:3.9em}.iah-chips{list-style:none;display:flex;flex-wrap:wrap;gap:6px;margin:4px 0 10px;padding:0}.iah-chips li{font:600 12px var(--body);border:1px solid var(--band-line);background:var(--band);border-radius:999px;padding:3px 10px;color:var(--frame)}:root[data-theme="dark"] .iah-chips li{color:var(--frame-ink)}.iah-card .btn{justify-content:center;margin-top:auto;text-align:center}.iah-glink{align-self:center;font:600 14px var(--body);color:var(--ink);padding:10px 4px;min-height:44px;box-sizing:border-box;display:inline-flex;align-items:center;text-decoration:underline;text-decoration-color:var(--band-line);text-decoration-thickness:2px;text-underline-offset:5px}.iah-glink:hover{color:var(--lamp)}.iah-nav{position:absolute;top:38%;width:44px;height:44px;border-radius:50%;border:1px solid var(--band-line);background:var(--card);color:var(--frame);font:700 26px/1 var(--body);cursor:pointer;box-shadow:0 4px 12px rgba(27,42,74,.18);display:grid;place-items:center;padding:0 0 3px}:root[data-theme="dark"] .iah-nav{color:var(--frame-ink)}.iah-nav:hover{border-color:var(--gold)}.iah-nav.prev{left:-22px}.iah-nav.next{right:-22px}.iah-dots{display:flex;justify-content:center;gap:2px;margin-top:2px}.iah-dots button{width:28px;height:28px;border:0;background:none;cursor:pointer;padding:0;position:relative}.iah-dots button:after{content:"";position:absolute;left:9px;top:9px;width:10px;height:10px;border-radius:50%;background:var(--band-line);border:1px solid var(--frame)}.iah-dots button[aria-current=true]:after{background:var(--gold);border-color:var(--gold)}@media(max-width:760px){.iah-card{flex-basis:82vw}.iah-nav{display:none}.iah-track{margin:0 -16px;padding:6px 16px 16px;scroll-padding:0 16px}}@media(prefers-reduced-motion:reduce){.iah-track{scroll-behavior:auto}}/* lead fixes 2026-10-22: arrows sit outside the cards; every card art box is the same height */.iah-nav.prev{left:-62px}.iah-nav.next{right:-62px}@media (max-width:1280px){.iah-nav{display:none}}.iah-card .hcart{height:150px;overflow:hidden;display:flex;align-items:center;justify-content:center;border-radius:10px}.iah-card .hcart>svg,.iah-card .hcart>img{max-height:100%;width:auto;max-width:100%}.iah-slider{width:min(1180px,calc(100vw - 48px));left:50%;transform:translateX(-50%)}@media (max-width:760px){.iah-slider{width:auto;left:auto;transform:none}}.iah-buy{justify-content:center}.iah-note a{color:var(--ink-2);font-weight:600}/* premium PDF library: sales page + /library/pdfs/ app */.lib-counts{list-style:none;margin:10px 0;padding:0;display:grid;gap:4px}.lib-counts li{color:var(--ink-2);font-size:14.5px}.lib-counts b{color:var(--ink);font:700 16px var(--head);margin-right:4px}.lib-course h3{margin:4px 0 6px}.pl-courses{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 14px}.pl-course{border:1px solid var(--edge);background:var(--desk-2);color:var(--text);border-radius:999px;padding:8px 14px;font:500 14px var(--body);cursor:pointer}.pl-course[aria-pressed="true"]{background:var(--navy);color:var(--on-navy);border-color:var(--navy);font-weight:700}.pl-status{background:var(--desk-2);border:1px solid var(--edge);border-left:4px solid var(--lamp);border-radius:12px;padding:12px 16px;color:var(--dim);display:flex;flex-wrap:wrap;gap:8px 14px;align-items:center}.pl-status b{color:var(--text)}.pl-status .btn{padding:8px 14px;font-size:14px}.pl-tabs{display:flex;gap:4px;border-bottom:1px solid var(--edge);margin:22px 0 18px;overflow-x:auto}.pl-tab{background:none;border:0;border-bottom:3px solid transparent;color:var(--dim);font:600 15px var(--head);padding:10px 14px;cursor:pointer;white-space:nowrap}.pl-tab[aria-selected="true"]{color:var(--lamp);border-bottom-color:var(--lamp)}.pl-intro,.pl-empty{color:var(--dim);margin:0 0 14px}.pl-intro .btn{margin-right:10px}.pl-topics{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.pl-topic{background:var(--paper);color:var(--ink);border-radius:14px;padding:14px 16px;min-width:0}.pl-topic h3{font-size:16px;margin:0 0 10px;color:var(--ink)}.pl-acts{display:flex;flex-wrap:wrap;gap:6px}.pl-open,.pl-go,.pl-lock{text-decoration:none;display:inline-block;border-radius:999px;padding:6px 12px;font:500 13px var(--body);border:1px solid var(--line2);background:var(--card);color:var(--ink);cursor:pointer}.pl-open:hover,.pl-go:hover{border-color:var(--coral-ink);color:var(--coral-ink)}.pl-open.free{border-color:var(--mint);color:var(--ok-t)}.pl-lock{cursor:default;color:var(--mute);background:var(--tint);border-style:dashed}.pl-lock:before{content:"🔒 ";font-size:11px}.pl-basics{list-style:none;margin:0;padding:0;display:grid;gap:6px}.pl-basics li{display:flex;flex-wrap:wrap;align-items:center;gap:6px;font-size:14px;color:var(--ink-2)}.pl-basics li span{flex:1 1 100%}.pl-viewer{position:fixed;inset:0;z-index:80;background:rgba(27,42,74,.5);display:grid;place-items:center;padding:max(12px,env(safe-area-inset-top,0px)) max(12px,env(safe-area-inset-right,0px)) 12px max(12px,env(safe-area-inset-left,0px))}.pl-viewer[hidden]{display:none}.plv-box{width:min(1100px,100%);height:min(92vh,100%);background:var(--desk-2);border:1px solid var(--edge);border-radius:16px;display:flex;flex-direction:column;overflow:hidden}.plv-bar{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:10px 14px;border-bottom:1px solid var(--edge)}.plv-bar b{color:var(--text);font:600 15px var(--head);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.plv-bar span{display:flex;gap:8px;flex:none}.plv-bar .btn{padding:7px 12px;font-size:13.5px}#plvFrame{flex:1;border:0;background:#fff;width:100%}.ac-msg.bad{border-color:var(--coral)}@media(max-width:760px){.pl-topics{grid-template-columns:minmax(0,1fr)}}.lib-acts{display:flex;flex-wrap:wrap;gap:8px}.lib-paynote{margin-top:14px}.pl-paynote{flex:1 1 100%;font-size:13.5px;color:var(--dim)}/* signed in: which courses you have */.pl-course.own:after{content:" ✓";color:var(--mint)}.pl-course.locked:after{content:" 🔒";font-size:11px}.pl-course.own[aria-pressed="true"]:after{color:var(--ink)}button.pl-lock{cursor:pointer;font:500 13px var(--body)}button.pl-lock:hover{border-color:var(--coral-ink);color:var(--coral-ink)}.pl-status.pulse{animation:plpulse 1.2s ease-out}@keyframes plpulse{0%{box-shadow:0 0 0 0 var(--gold-b)}100%{box-shadow:0 0 0 14px rgba(169,116,42,0)}}@media (prefers-reduced-motion:reduce){.pl-status.pulse{animation:none}}/* simple list (2026-10-20): one row per topic, fixed columns, one click to open */.pl-tbl{background:var(--card);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1);overflow:hidden}.pl-tr{display:grid;grid-template-columns:minmax(0,2.2fr) repeat(4,minmax(0,1fr));gap:8px 12px;align-items:center;padding:10px 18px;border-top:1px solid var(--line)}.pl-tr:first-child{border-top:0}.pl-th{background:var(--desk-2);font:600 12px var(--body);text-transform:uppercase;letter-spacing:.12em;color:var(--ink-2);padding-block:12px}.pl-tn{font:700 15.5px var(--head);letter-spacing:-.01em;color:var(--ink)}.pl-tr>span{display:flex;flex-wrap:wrap;gap:6px}.pl-tr .pl-open,.pl-tr .pl-go,.pl-tr .pl-lock{padding:5px 12px;font-size:13.5px}.pl-tr .pl-na{color:var(--mute);padding-left:6px}@media(max-width:760px){.pl-th{display:none}.pl-tr{grid-template-columns:repeat(2,minmax(0,1fr));padding:12px 14px}.pl-tn{grid-column:1/-1}.pl-tr>span:before{content:attr(data-l);display:block;flex:1 1 100%;font:600 11px var(--body);text-transform:uppercase;letter-spacing:.1em;color:var(--ink-2)}.pl-tr>span{align-content:start}}.pl-topics{display:block;background:var(--card);border:1px solid var(--line);border-radius:var(--rl);box-shadow:var(--sh1);overflow:hidden}.pl-topic{background:none;border-radius:0;padding:12px 18px;border-top:1px solid var(--line)}.pl-topic:first-child{border-top:0}.pl-topic h3{margin:0 0 8px}.pl-tabs{margin-top:14px}/* Premium library (lean sweep): "what every course includes" strip + subject rows with HL | SL cells */.lt-inc{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(5,1fr);gap:0;background:var(--card);border:1px solid var(--line);border-top:4px solid var(--frame);border-radius:var(--rl);box-shadow:var(--sh1)}.lt-inc li{padding:22px 14px;text-align:center;border-left:1px solid var(--line);display:grid;gap:4px;justify-items:center}.lt-inc li:first-child{border:0}.lt-inc b{font:800 16px var(--head);color:var(--ink)}.lt-inc li>span:last-child{font-size:13px;color:var(--dim)}.lt-ic{width:46px;height:46px;border-radius:12px;display:grid;place-items:center;background:var(--tint);color:var(--frame);margin-bottom:6px}:root[data-theme=dark] .lt-ic{color:var(--frame-ink,#e8ecf3)}.lt-table{display:grid;gap:12px;max-width:1000px;margin:0 auto}.lt-row{display:grid;grid-template-columns:200px 1fr 1fr;gap:0;align-items:center;background:var(--card);border:1px solid var(--line);border-left:4px solid var(--frame);border-radius:var(--rs);box-shadow:var(--sh1)}.lt-n{font:800 20px var(--head);margin:0;padding:18px 20px;color:var(--ink)}.lt-cell{padding:16px 20px;border-left:1px solid var(--line);display:grid;gap:8px;justify-items:start}.lt-lv{margin:0;font-size:13px;color:var(--dim)}.lt-lv b{font:800 16px var(--head);color:var(--ink);margin-right:6px}.lt-cell .btn{height:42px;padding:0 18px}.lt-in{font-size:13.5px;font-weight:600;color:var(--ink);text-decoration:none;border-bottom:1px solid var(--gold)}@media(max-width:760px){.lt-inc{grid-template-columns:repeat(2,1fr)}.lt-inc li{border-top:1px solid var(--line);padding:16px 8px}.lt-inc li:nth-child(odd){border-left:0}.lt-inc li:nth-child(-n+2){border-top:0}.lt-inc li:last-child{grid-column:1/-1}.lt-row{grid-template-columns:1fr 1fr}.lt-n{grid-column:1/-1;padding:14px 16px 4px}.lt-cell{border-left:0;padding:8px 16px 16px}.lt-cell+.lt-cell{border-left:1px solid var(--line)}.lt-cell .btn{width:100%;padding:0 8px}}/* main menu: dropdowns on desktop, one panel on phones and portrait tablets */header.site .wrap{position:relative}nav.main>ul{align-items:center}nav.main summary{list-style:none;cursor:pointer;color:var(--dim);font-weight:500;font-size:15px;padding:8px 11px;border-radius:999px;display:flex;align-items:center;gap:6px;user-select:none}nav.main summary::-webkit-details-marker{display:none}nav.main summary:after{content:"";width:6px;height:6px;border:solid currentColor;border-width:0 1.6px 1.6px 0;transform:translateY(-2px) rotate(45deg);transition:transform .2s}nav.main details[open] summary:after{transform:translateY(1px) rotate(-135deg)}nav.main summary:hover,nav.main details[open] summary{color:var(--text);background:var(--hov)}nav.main summary.on{background:var(--gold-t);color:var(--lamp)}nav.main summary:focus-visible{outline:2px solid var(--lamp);outline-offset:2px}nav.main .dd{position:relative}nav.main .ddp{position:absolute;top:calc(100% + 10px);left:50%;transform:translateX(-50%);list-style:none;margin:0;padding:8px;width:300px;display:grid;gap:2px;background:var(--desk-2);border:1px solid var(--edge);border-radius:16px;box-shadow:var(--sh1);animation:ddin .18s ease-out}nav.main .ddp.two{width:520px;grid-template-columns:1fr 1fr}nav.main .ddp a{display:block;border-radius:10px;padding:10px 12px;color:var(--text)}nav.main .ddp a b{display:block;font:600 14.5px/1.3 var(--head);letter-spacing:-.01em}nav.main .ddp a span{display:block;font-size:12.5px;line-height:1.4;color:var(--dim);margin-top:3px}nav.main .ddp a:hover{background:var(--gold-t)}nav.main .ddp a:hover b{color:var(--lamp)}@keyframes ddin{from{opacity:0;transform:translate(-50%,-6px)}to{opacity:1;transform:translate(-50%,0)}}@media(prefers-reduced-motion:reduce){nav.main .ddp{animation:none}}.hright{display:flex;align-items:center;gap:10px}.burger{display:none}@media(max-width:1220px){nav.main{display:none}.burger{display:block}.burger summary{list-style:none;cursor:pointer;width:44px;height:44px;border-radius:12px;border:1px solid var(--edge);display:grid;place-content:center;gap:4px}.burger summary::-webkit-details-marker{display:none}.burger summary i{display:block;width:18px;height:2px;border-radius:2px;background:var(--text);transition:transform .2s,opacity .2s}.burger[open] summary i:nth-child(1){transform:translateY(6px) rotate(45deg)}.burger[open] summary i:nth-child(2){opacity:0}.burger[open] summary i:nth-child(3){transform:translateY(-6px) rotate(-45deg)}.mpanel{position:absolute;left:0;right:0;top:66px;max-height:calc(100dvh - 66px - env(safe-area-inset-top,0px));overflow-y:auto;background:var(--desk);border-bottom:1px solid var(--edge);padding:8px max(16px,env(safe-area-inset-right,0px)) 24px max(16px,env(safe-area-inset-left,0px));box-shadow:var(--sh1)}.mpanel>ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:4px 24px}.mpanel ul ul{list-style:none;margin:0 0 10px;padding:0}.mpanel .mh{font:500 11.5px var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--lamp);margin:14px 0 4px}.mpanel a{display:block;color:var(--text);text-decoration:none;padding:10px 0;font-size:16px;border-bottom:1px solid var(--edge)}.mpanel a.mtop{font:600 17px var(--head);padding:14px 0}.mpanel .signin.wide{display:block;text-align:center;margin-top:18px;border:0;padding:14px}}@media(max-width:420px){header.site .signin:not(.wide){display:none}}header.site details{background:none;padding:0;margin:0;border-radius:0;color:var(--text);border:0;box-shadow:none}header.site details p{margin:0}header.site details a{color:var(--text);text-decoration:none}header.site nav.main summary{font-family:var(--body);letter-spacing:0;justify-content:flex-start}header.site .burger summary:after{content:none}/* header search (2026-10-19) */.hsrch{display:inline-flex;align-items:center;gap:8px;background:var(--desk-3);border:1px solid var(--edge);border-radius:999px;color:var(--dim);font:500 14px var(--body);padding:8px 12px;cursor:pointer;min-width:170px}.hsrch:hover{color:var(--text);border-color:rgba(27,42,74,.2)}.hsrch kbd{margin-left:auto;font:500 11px var(--mono);border:1px solid var(--edge);border-radius:5px;padding:1px 5px}.signin small{font-weight:500;opacity:.7}@media(max-width:1180px){.hsrch{min-width:0}.hsrch span,.hsrch kbd{display:none}.hsrch{padding:9px;border-radius:50%}}.srch{position:fixed;inset:0;z-index:90;background:rgba(27,42,74,.5);display:grid;align-items:start;justify-items:center;padding:max(70px,env(safe-area-inset-top,0px)) max(16px,env(safe-area-inset-right,0px)) 16px max(16px,env(safe-area-inset-left,0px))}.srch[hidden]{display:none}.srch-box{width:min(680px,100%);background:var(--desk-2);border:1px solid var(--edge);border-radius:18px;box-shadow:var(--sh1);overflow:hidden}.srch-in{display:flex;align-items:center;gap:10px;padding:12px 14px;border-bottom:1px solid var(--edge);color:var(--dim)}.srch-in input{flex:1;min-width:0;background:none;border:0;outline:0;color:var(--text);font:500 17px var(--body)}.srch-x{background:var(--desk-3);border:1px solid var(--edge);color:var(--dim);border-radius:7px;font:500 12px var(--mono);padding:4px 8px;cursor:pointer}.srch-r{list-style:none;margin:0;padding:6px;max-height:min(60vh,520px);overflow:auto}.srch-r a{display:grid;gap:2px;padding:10px 12px;border-radius:12px;text-decoration:none;color:var(--text)}.srch-r a b{font:600 15px var(--head);letter-spacing:-.01em}.srch-r a span{color:var(--dim);font-size:13px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.srch-r a[aria-selected],.srch-r a:hover{background:var(--gold-t)}.srch-r a[aria-selected] b{color:var(--lamp)}.srch-m{color:var(--dim);padding:14px 12px;font-size:14px}@media(min-width:1001px) and (max-width:1340px){.hsrch span,.hsrch kbd,header.site .signin small{display:none}.hsrch{min-width:0;width:44px;height:44px;justify-content:center;padding:0;border-radius:10px}nav.main>ul>li>a,nav.main summary{padding:8px 9px;font-size:14px}header.site .wrap{gap:10px}}.hsrch{height:44px;border-radius:10px;background:var(--card)}/* one-page booklets (/print/*) and their download cards */.op-cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:0 0 22px}.op-card{display:flex;gap:14px;align-items:center;background:var(--desk-2);border:1px solid var(--edge);border-radius:16px;padding:12px;text-decoration:none;color:var(--text);min-width:0}.op-card:hover{border-color:var(--lamp)}.op-card img{width:42%;max-width:180px;height:auto;border-radius:6px;background:var(--card);box-shadow:var(--sh1);flex:none}.op-card span{display:flex;flex-direction:column;gap:4px;min-width:0}.op-card b{font:600 16px var(--head)}.op-card em{font-style:normal;font-size:13.5px;color:var(--dim);line-height:1.45}.op-card i{font-style:normal;color:var(--lamp);font-weight:600;font-size:14px}@media(max-width:700px){.op-cards{grid-template-columns:minmax(0,1fr)}}.op-sheet{background:#fff;color:#16181c;padding:6mm;max-width:210mm;margin:20px auto;font:400 8.6px/1.25 var(--body);color-scheme:light}.op-head{display:flex;flex-wrap:wrap;align-items:baseline;gap:2px 10px;border-bottom:1.5px solid #ff6a45;padding-bottom:3px;margin-bottom:4px}.op-brand{margin:0;font:700 11px var(--head);letter-spacing:-.02em}.op-brand i{font-style:normal;color:#ff6a45}.op-head h1{margin:0;font:700 12px var(--head);letter-spacing:-.02em;color:#16181c}.op-sub{margin:0 0 0 auto;font-size:7.5px;color:var(--ink-2)}.op-cols{column-count:4;column-gap:3.5mm;column-rule:.5px solid #e2dfd6}.op-sheet section{margin:0 0 3px}.op-sheet h2{font:700 8.8px var(--head);background:#16181c;color:#fff;margin:2px 0 1px;padding:1px 4px;border-radius:2px;break-after:avoid}.op-sheet h3{font:700 7.8px var(--head);margin:3px 0 0;color:#16181c;break-after:avoid}.op-sheet .it{break-inside:avoid;padding:1px 0;border-bottom:.5px dotted #e2dfd6}.op-sheet .lb{display:block;font-size:7px;color:var(--ink-2);font-weight:600}.op-sheet .fx .katex{font-size:1.08em}.op-sheet .hl{font-style:normal;font:700 6px var(--mono);background:#16181c;color:#fff;border-radius:2px;padding:0 2px;margin-left:2px;vertical-align:1px}.op-sheet .tip{display:inline-block;margin:1px 0 0;font-size:6.9px;line-height:1.2;color:var(--ok-t);background:#dff2e9;border-radius:2px;padding:0 3px;-webkit-print-color-adjust:exact;print-color-adjust:exact}.op-sheet .op-sub .tip{font-size:7px}.op-sheet .xb{break-inside:avoid;border:1px solid #0f8a66;background:#e9f6f0;border-radius:3px;padding:1px 3px;margin:2px 0;-webkit-print-color-adjust:exact;print-color-adjust:exact}.op-sheet .xb>p{margin:0;font:700 6.2px var(--mono);text-transform:uppercase;letter-spacing:.06em;color:#0f8a66}.op-sheet .xb .it{border-bottom-color:#b9e0cf}.op-sheet .xb .lb{color:var(--ok-t)}.op-t{border-collapse:collapse;width:100%;font-size:7px}.op-t td{padding:0 2px 1px 0;border-bottom:.5px dotted #e2dfd6;vertical-align:top}.op-t td:first-child{color:var(--ink-2)}.op-line{margin:1px 0;font-size:7.2px}.op-sym{display:grid;grid-template-columns:repeat(5,1fr);gap:1px}.op-sym figure{margin:0;text-align:center}.op-sym svg{width:100%;height:auto;fill:none;stroke:#16181c;stroke-width:3;stroke-linecap:round}.op-sym svg text{fill:#16181c;stroke:none;font:600 20px var(--body)}.op-sym figcaption{font-size:5.6px;line-height:1.1;color:var(--ink-2)}.op-foot{margin:4px 0 0;font-size:6.4px;color:var(--ink-2);border-top:.5px solid #e2dfd6;padding-top:2px}@media print{.op-sheet{margin:0;padding:0;max-width:none}.op-sheet h2,.op-sheet .hl{-webkit-print-color-adjust:exact;print-color-adjust:exact}}.op-sheet .f{display:block;overflow:hidden;white-space:nowrap}.op-sheet .f .katex{white-space:nowrap}.op-sheet .f.wrap{white-space:normal;overflow:visible}.op-sheet .f.wrap .katex{white-space:normal}@media print{.op-sheet{page:onesheet}}@page onesheet{size:A4;margin:6mm}.op-h{font-size:20px;margin:6px 0 12px;color:var(--text)}/* booklet hub */.op-sl{font-size:14.5px;color:var(--dim);margin:-8px 0 22px}.op-sl b{color:var(--text)}.op-sl a{color:var(--lamp)}.bk-guide{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-bottom:22px}.bk-guide>div{background:var(--desk-2);border:1px solid var(--edge);border-radius:16px;padding:16px 18px}.bk-guide .n{display:inline-grid;place-items:center;width:26px;height:26px;border-radius:50%;background:var(--navy);color:var(--on-navy);font:700 13px var(--head);margin-bottom:8px}.bk-guide b{display:block;font:600 16px var(--head);color:var(--text)}.bk-guide p{margin:4px 0 0;font-size:14px;color:var(--dim);line-height:1.5}.bk-subj{display:grid;grid-template-columns:minmax(0,230px) minmax(0,1fr);gap:28px;align-items:start;background:var(--paper);color:var(--ink);border-radius:22px;padding:clamp(18px,3vw,30px);margin:0 0 18px;scroll-margin-top:90px}.bk-prev img{width:100%;height:auto;border-radius:6px;box-shadow:var(--sh1);border:1px solid var(--line);display:block}.bk-main{min-width:0}.bk-main .eyebrow{color:var(--coral-ink)}.bk-main h2{margin:4px 0 4px;font-size:clamp(23px,2.8vw,30px);color:var(--ink)}.bk-src{margin:0 0 14px;font-size:14px;color:var(--ink-2)}.bk-formats{list-style:none;margin:16px 0 10px;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.bk-formats a{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:0 10px;align-items:center;border:1px solid var(--line);border-radius:12px;padding:10px 12px;text-decoration:none;color:var(--ink)}.bk-formats a:hover{border-color:var(--coral-ink);background:var(--card)}.bk-formats b{font:600 14.5px var(--head)}.bk-formats span{grid-column:1;font-size:12.5px;color:var(--ink-2)}.bk-formats i{grid-row:1/3;grid-column:2;font:500 11px var(--mono);font-style:normal;color:var(--coral-ink);border:1px solid var(--line);border-radius:6px;padding:3px 6px}.bk-main .note a{color:var(--coral-ink)}@media(max-width:820px){.bk-guide{grid-template-columns:minmax(0,1fr)}.bk-subj{grid-template-columns:minmax(0,1fr)}.bk-prev{max-width:150px}.bk-formats{grid-template-columns:minmax(0,1fr)}}.bk-formats{align-items:start}.bk-formats .grp>p{margin:0 0 6px;font:500 11px var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--ink-2)}.bk-formats .grp ul{list-style:none;margin:0;padding:0;display:grid;gap:8px}.op-dt{font-size:6.4px}.op-dt th{text-align:left;font-weight:700;border-bottom:.5px solid #16181c}/* booklets hub, lean: 2x2 cards with one PDF row each */.bk-how{list-style:none;margin:0 0 18px;padding:0;display:flex;flex-wrap:wrap;gap:8px 10px}.bk-how li{border:1px solid var(--edge);border-radius:999px;padding:6px 14px;font-size:14px;color:var(--dim);background:var(--desk-2)}.bk-how b{color:var(--text);margin-right:4px}.bk-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin-top:18px}.bk-grid .bk-subj{grid-template-columns:minmax(0,110px) minmax(0,1fr);gap:18px;margin:0;border:1px solid var(--line);border-top:3px solid var(--frame)}.bk-lab{margin:14px 0 6px;font:500 11px var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--ink-2)}.bk-chips{display:flex;flex-wrap:wrap;gap:6px}.bk-chip{border:1px solid var(--line);border-radius:999px;padding:6px 12px;font:600 13.5px var(--head);text-decoration:none;color:var(--ink)}.bk-chip:hover{border-color:var(--coral-ink);background:var(--card)}.bk-sl{margin:10px 0 0;padding:0;background:none;border:0;box-shadow:none;border-radius:0}.bk-sl summary{font:600 13.5px var(--head);color:var(--coral-ink);justify-content:flex-start;gap:6px}.bk-sl summary:after{content:"+";font-size:16px}.bk-sl[open] summary:after{content:"\2212"}.bk-sl .bk-chips{margin-top:8px}@media(max-width:900px){.bk-grid{grid-template-columns:minmax(0,1fr)}}@media(max-width:480px){.bk-grid .bk-subj{grid-template-columns:minmax(0,72px) minmax(0,1fr);gap:12px}}/* Paper 3 guides (tools/pages_paper3.py): option C, a short course in 4 steps, one open at a time */.p3-wrap{max-width:860px}.p3-hero{padding-bottom:30px}.p3-hero h1{font-size:clamp(32px,4.4vw,50px)}.p3-facts{list-style:none;margin:22px 0 0;padding:0;display:flex;flex-wrap:wrap;gap:8px 26px;font-size:14px;color:var(--dim)}.p3-facts b{display:block;font:800 22px var(--head);letter-spacing:-.02em;color:var(--ink)}.p3-progress{display:flex;align-items:center;gap:12px;margin:26px 0 12px}.p3-prog{flex:1;height:6px;border-radius:3px;background:var(--tint);overflow:hidden}.p3-prog i{display:block;width:0;height:100%;background:var(--lv-f);transition:width .3s}.p3-count{font:600 13px var(--body);color:var(--mute);white-space:nowrap;font-variant-numeric:tabular-nums}.p3-path{display:grid;gap:10px}details.p3s{border-radius:var(--rl);padding:0;scroll-margin-top:90px}details.p3s>summary{display:grid;grid-template-columns:40px minmax(0,1fr) auto;gap:14px;align-items:center;padding:16px 18px;cursor:pointer;list-style:none}details.p3s>summary::-webkit-details-marker{display:none}.p3-n{width:40px;height:40px;border-radius:50%;background:var(--tint);color:var(--dim);font:800 16px/40px var(--head);text-align:center}details.p3s[open] .p3-n{background:linear-gradient(var(--btn1),var(--btn2));color:var(--on-navy)}details.p3s.done .p3-n{background:var(--lv-f);color:#fff;font-size:0}details.p3s.done .p3-n:after{content:"✓";font-size:18px}.p3-st b,.p3-st h2{display:block;margin:0;font:700 17px var(--head);letter-spacing:-.01em;color:var(--ink)}.p3-st small{display:block;font-size:13.5px;color:var(--mute);line-height:1.4}.p3-min{font:600 12.5px var(--body);color:var(--mute);white-space:nowrap}.p3-body{padding:0 18px 20px 72px;font-size:16px}@media(max-width:640px){.p3-body{padding:0 16px 18px}.p3-min{display:none}details.p3s>summary{grid-template-columns:40px minmax(0,1fr)}}.p3-body>p,.p3-body>h3,.p3-body>ol,.p3-body>div{margin:0 0 14px}.p3-body h3{font-size:17px;margin-top:22px}.p3-next{margin:18px 0 0!important}.p3-arc{list-style:none;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px 16px}@media(max-width:640px){.p3-arc{grid-template-columns:1fr}}.p3-arc li{border-top:3px solid var(--gold);padding-top:8px;font-size:14px;color:var(--dim)}.p3-arc b{display:block;font:700 15px var(--head);color:var(--ink)}.p3-types{display:grid;gap:6px}.p3-types>details{border-radius:var(--rs);padding:0;box-shadow:none}.p3-types>details>summary{display:flex;justify-content:space-between;gap:12px;align-items:baseline;padding:12px 14px;cursor:pointer}.p3-types>details>summary b,.p3-types>details>summary h3{margin:0;font:700 15.5px var(--head)}.p3-types>details>summary small{color:var(--mute);font-size:13px;white-space:nowrap}.p3-tb{padding:0 14px 14px;font-size:15px}.p3-tb h4{font:600 12px var(--body);text-transform:uppercase;letter-spacing:.1em;color:var(--mute);margin:14px 0 6px}.p3-tb ul,.p3-tb ol{margin:0;padding-left:20px;display:grid;gap:5px}.p3-bad li::marker{color:var(--lv-x)}.p3-gdc{margin-top:12px;background:var(--tint);border-radius:10px;padding:10px 12px}.p3-more{margin-top:12px;font-weight:600}.p3-wt{font-size:17px}.p3-tip{font-size:14px;color:var(--dim);background:var(--tint);border-radius:10px;padding:10px 12px}.p3-wi{display:grid;gap:10px}.p3-part{border:1px solid var(--line);border-radius:var(--rs);padding:12px 14px;background:var(--card)}.p3-part>p{margin:0 0 6px}.p3-mk{color:var(--mute);font-size:14px;white-space:nowrap}.p3-part details{box-shadow:none;border:0;background:none;padding:0}.p3-part summary{font-weight:600;color:var(--lamp);cursor:pointer;font-size:14.5px}.p3-sol{margin:10px 0 0;padding-left:20px;display:grid;gap:8px}.p3-sol li{display:flex;flex-wrap:wrap;gap:4px 10px;align-items:baseline}.p3-sol .p3-w{min-width:0;max-width:100%;overflow-x:auto}.p3-m{font:700 12px var(--body);font-style:normal;color:var(--lv-c);border:1px solid currentColor;border-radius:5px;padding:1px 6px}.p3-sol small{flex-basis:100%;color:var(--dim);font-size:13.5px}.p3-time{list-style:none;padding:0;display:grid;gap:10px}.p3-time li{display:grid;grid-template-columns:78px minmax(0,1fr);gap:12px;font-size:15px}.p3-time b{font:700 14px var(--body);color:var(--lamp);font-variant-numeric:tabular-nums}.p3-time strong{font-weight:600;color:var(--ink)}.p3-after .faqwrap{margin-bottom:28px}.p3-cta{padding:20px;border-radius:var(--rl);background:var(--tint);display:flex;flex-wrap:wrap;gap:14px;align-items:center;justify-content:space-between}.p3-cta b{font:700 17px var(--head)}.p3-cta p{margin:2px 0 0;font-size:14px;color:var(--dim);max-width:52ch}.p3-links{margin-top:18px;font-size:14px;color:var(--mute)}.katex-display{overflow-x:auto;overflow-y:hidden;padding:2px 0}@media(prefers-reduced-motion:reduce){.p3-prog i{transition:none}}details.p3s>summary:after{display:none}.p3-path,.p3-types,.p3-wi{grid-template-columns:minmax(0,1fr)}.p3-path>*,.p3-types>*,.p3-wi>*,.p3-body{min-width:0}.p3-side{display:none}@media(min-width:1180px){.p3-wrap{max-width:1140px}.p3-layout{display:grid;grid-template-columns:minmax(0,1fr) 270px;gap:28px;align-items:start}.p3-hero .p3-prog-m{display:none}.p3-hero .p3-lede,.p3-hero .lede,.p3-facts{max-width:760px}.p3-side{display:flex;flex-direction:column;gap:12px;position:sticky;top:96px;padding:18px;border:1px solid var(--line);border-top:3px solid var(--navy,#0b2a5b);border-radius:var(--rl)}.p3-side .p3-progress{margin:0}.p3-sl{font-size:14px;font-weight:600}}/* web practice questions (/library/practice/, static/js/practice.js) */.pq-empty,.pq-note{color:var(--dim)}.pq-back{margin:0 0 12px;font-size:14px}.pq-back a{color:var(--dim);text-decoration:none}.pq-back a:hover{color:var(--text)}.pq-lock{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:6px 16px;align-items:center;background:linear-gradient(160deg,var(--gold-t),var(--gold-t));border:1px solid var(--gold-b);border-radius:16px;padding:14px 16px;margin:0 0 16px}.pq-lock b{display:block;color:var(--text);font:700 15.5px var(--head)}.pq-lock span{color:var(--dim);font-size:14px}.pq-lock small{grid-column:1/-1;color:var(--dim);font-size:12.5px}@media(max-width:640px){.pq-lock{grid-template-columns:minmax(0,1fr)}.pq-lock .btn{justify-self:start}}.pq-topics{display:grid;gap:12px;grid-template-columns:repeat(auto-fill,minmax(min(100%,300px),1fr))}.pq-topic{background:var(--desk-3);border:1px solid var(--edge);border-radius:16px;padding:14px;min-width:0}.pq-topic h3{font-size:17px;margin:0 0 10px}.pq-lvls{display:grid;gap:8px}.pq-lvl{display:grid;grid-template-columns:auto minmax(0,1fr);gap:2px 10px;align-items:center;background:var(--desk-2);border:1px solid var(--edge);border-radius:12px;padding:10px 12px;text-decoration:none;color:var(--text)}.pq-lvl:hover{border-color:var(--lamp)}.pq-lvl b{font:700 14.5px var(--head)}.pq-lvl span{color:var(--dim);font-size:13px;text-align:right}.pq-lvl small{grid-column:2;text-align:right;color:var(--dim);font-size:12px}.pq-bar{display:block;height:6px;border-radius:99px;background:var(--hov);overflow:hidden;grid-column:1/-1}.pq-bar>i{display:block;height:100%;background:var(--mint)}.pq-levels{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px;margin:0 0 14px}.pq-lv{display:grid;gap:2px;background:var(--desk-3);border:1px solid var(--edge);border-radius:14px;padding:12px 14px;text-decoration:none;color:var(--text)}.pq-lv small{font:500 11px var(--mono);color:var(--dim)}.pq-lv b{font:700 16px var(--head)}.pq-lv span{color:var(--dim);font-size:13px}.pq-lv[aria-current]{border-color:var(--lamp);background:var(--gold-t)}.pq-lv[aria-current] b{color:var(--lamp)}.pq-lv.off{opacity:.55}.pq-dl{display:flex;flex-wrap:wrap;align-items:center;gap:8px 12px;margin:0 0 14px}.pq-dl small{color:var(--dim);font-size:13px}.pq-prog{display:flex;flex-wrap:wrap;align-items:center;gap:10px 18px;background:var(--desk-2);border:1px solid var(--edge);border-radius:14px;padding:12px 16px;margin:0 0 14px;font-size:14px;color:var(--dim)}.pq-prog b{color:var(--text)}.pq-prog .pq-bar{flex:1 1 160px;min-width:120px;height:8px}.pq-filters{display:flex;flex-wrap:wrap;gap:8px 16px;margin:0 0 16px;align-items:center}.pq-fg{display:flex;flex-wrap:wrap;gap:4px;align-items:center}.pq-fg>span{font:500 11px var(--mono);color:var(--dim);text-transform:uppercase;letter-spacing:.06em;margin-right:4px}.pq-fb{background:var(--desk-3);border:1px solid var(--edge);border-radius:999px;padding:5px 11px;font:500 13px var(--body);color:var(--dim);cursor:pointer}.pq-fb[aria-pressed="true"]{background:var(--navy);color:var(--on-navy);border-color:var(--navy);font-weight:700}.pq-grp{font-size:19px;margin:24px 0 10px}.pq-grp small{font:500 12px var(--mono);color:var(--dim);letter-spacing:0}.pq-card{background:var(--paper);color:var(--ink);border-radius:18px;margin:0 0 14px;overflow:hidden;border:1px solid transparent;min-width:0}.pq-card.got{border-color:var(--ok-b)}.pq-card.review{border-color:var(--gold-b)}.pq-ch{display:flex;flex-wrap:wrap;align-items:center;gap:6px 8px;padding:14px 18px 0}.pq-ch h3{font-size:17px;margin:0 8px 0 0;color:var(--ink)}.pq-ch h3 small{font:500 13px var(--body);color:var(--ink-2)}.pq-chip{font:500 12px var(--mono);border-radius:999px;padding:3px 9px;border:1px solid var(--line);color:var(--ink-2);background:var(--card);white-space:nowrap}.pq-chip.Easy{color:var(--ok-t);border-color:var(--ok-b);background:var(--ok-bg)}.pq-chip.Medium{color:var(--warn-t);border-color:var(--warn-b);background:var(--warn-bg)}.pq-chip.Hard{color:var(--bad-t);border-color:var(--bad-b);background:var(--bad-bg)}.pq-chip.free{color:var(--ok-t);border-color:var(--ok-b)}.pq-chip.st{margin-left:auto}.pq-chip.st.got{background:var(--ok-bg);color:var(--ok-t);border-color:var(--ok-b)}.pq-chip.st.review{background:var(--bad-bg);color:var(--bad-t);border-color:var(--bad-b)}.pq-q{padding:6px 18px 4px;font-size:16px;line-height:1.65;overflow-wrap:break-word}.pq-q p,.pq-step p{margin:.45em 0}.pq-parts{list-style:lower-alpha;margin:.4em 0;padding-left:1.7em}.pq-parts li{margin:.35em 0}.pq-parts li.pq-li{list-style:none;margin-left:-1.7em}.pq-li>b:first-child{display:inline-block;min-width:1.7em}.pq-pm{float:right;font:500 13px var(--mono);color:var(--ink-2);margin-left:8px}.pq-fig{display:block;max-width:min(100%,520px);height:auto;margin:10px auto}.pq-t{border-collapse:collapse;margin:8px 0;font-size:15px}.pq-t td{border:1px solid var(--line);padding:4px 10px;text-align:center}.pq-card .katex-display{overflow-x:auto;overflow-y:hidden;padding:2px 0}.pq-acts{display:flex;flex-wrap:wrap;gap:8px;padding:10px 18px 16px}.pq-b{border:1px solid var(--line);background:var(--card);color:var(--ink);border-radius:999px;padding:8px 14px;font:600 14px var(--body);cursor:pointer}.pq-b.pri{background:var(--ink);color:var(--on-navy);border-color:var(--ink)}.pq-b.timer.on{background:var(--bad-bg);border-color:var(--bad-b);color:var(--bad-t)}.pq-b.got{background:var(--ok-bg);border-color:var(--ok-b);color:var(--ok-t)}.pq-b.rev{background:var(--bad-bg);border-color:var(--bad-b);color:var(--bad-t)}.pq-ms{border-top:1px dashed var(--line);background:var(--tint);padding:12px 18px 6px}.pq-ms h4{font:600 12px var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink-2);margin:4px 0 8px;display:flex;justify-content:space-between;gap:10px}.pq-ms h4 em{font-style:normal;text-transform:none;letter-spacing:0;color:var(--coral-ink)}.pq-ms .more{margin:8px 0 4px}.pq-steps{display:grid;gap:2px;grid-template-columns:minmax(0,1fr)}.pq-step{padding:6px 10px;border-left:3px solid var(--line);border-radius:0 8px 8px 0;line-height:1.6;min-width:0;overflow-wrap:break-word}.pq-step[hidden]{display:none}.pq-step.new{animation:pqin .35s ease-out}@keyframes pqin{from{background:var(--hl)}to{background:transparent}}@media (prefers-reduced-motion:reduce){.pq-step.new{animation:none}}.pq-stp{font-weight:700;color:#24406b;margin-right:4px}.pq-mks{display:inline-flex;gap:4px;margin-left:6px;vertical-align:middle;flex-wrap:wrap}.pq-mk{font:600 12px var(--mono);border:1.5px solid var(--line3);background:var(--card);color:var(--ink-2);border-radius:7px;padding:2px 7px;cursor:pointer}.pq-mk.on{background:var(--mint);border-color:var(--mint);color:var(--on-navy)}.pq-mk[data-m="AG"]{cursor:default;border-style:dashed;opacity:.8}.pq-score{display:flex;flex-wrap:wrap;align-items:center;gap:8px 14px;padding:10px 18px 14px;background:var(--tint);border-top:1px solid var(--line);font-size:14px;color:var(--ink-2)}.pq-score[hidden],.pq-ms[hidden]{display:none}.pq-score .big{font:700 18px var(--head);color:var(--ink)}.pq-score .sp{flex:1}.pq-stepper{display:inline-flex;align-items:center;border:1px solid var(--line);border-radius:999px;background:var(--card)}.pq-stepper button{border:0;background:none;width:34px;height:32px;font-size:18px;cursor:pointer;color:var(--ink)}.pq-stepper .sc{min-width:28px;text-align:center;font:700 15px var(--head);color:var(--ink)}@media(max-width:700px){.pq-levels{grid-template-columns:repeat(2,minmax(0,1fr))}.pq-ch h3{width:100%}.pq-chip.st{margin-left:0}}.pq-q blockquote,.pq-step blockquote{margin:.5em 0;padding:6px 12px;border-left:3px solid var(--line);color:var(--ink-2)}/* one difficulty scale (course page, topic page, switches, question sheet) */.pq-status{display:flex;flex-wrap:wrap;align-items:center;gap:8px 16px;justify-content:space-between;background:var(--desk-2);border:1px solid var(--edge);border-radius:14px;padding:10px 16px;margin:0 0 14px;font-size:14.5px;color:var(--dim)}.pq-status b{color:var(--text)}.pq-status.own{justify-content:flex-start;border-color:var(--ok-b)}.pq-status.own b{color:var(--ok-t)}.pq-sum{color:var(--dim);font-size:14px;margin:0 0 10px}.pq-sum b{color:var(--text)}.pq-h2{font-size:20px;margin:24px 0 10px}.pq-vh{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}.pq-tw{border:1px solid var(--edge);border-radius:16px;overflow-x:auto;background:var(--desk-3)}.pq-tbl{width:100%;border-collapse:collapse;font-size:14px}.pq-tbl th{text-align:left;font:500 11px var(--mono);text-transform:uppercase;letter-spacing:.06em;color:var(--dim);padding:10px 12px;background:var(--desk-2);border-bottom:1px solid var(--edge);white-space:nowrap}.pq-tbl th small{display:none}.pq-tbl td{padding:9px 10px;border-bottom:1px solid var(--edge);vertical-align:middle}.pq-tbl tr:last-child td{border-bottom:0}.pq-tbl tbody tr:hover{background:var(--gold-t)}.pq-tn{display:block;font:700 15px var(--head);color:var(--text);text-decoration:none}.pq-tn:hover{color:var(--lamp)}.pq-tbl td>small{display:block;color:var(--dim);font-size:12px}.pq-go{text-align:right;white-space:nowrap}.pq-go .btn{padding:6px 14px;font-size:13.5px}.pq-pdf{border-radius:999px;padding:5px 12px;font:500 13px var(--body);border:1px solid var(--line2);background:var(--card);color:var(--ink);cursor:pointer;white-space:nowrap}.pq-pdf:hover{border-color:var(--coral-ink);color:var(--coral-ink)}.pq-pdf.free{border-color:var(--mint);color:var(--ok-t)}.pq-pdf.off{cursor:pointer;color:var(--mute);background:var(--tint);border-style:dashed}.pq-pdf[hidden]{display:none}.pq-fr{display:inline!important;margin-left:6px;color:var(--ok-t)!important;font:500 11px var(--mono)}.pq-none{color:var(--dim)}.pq-segs{display:grid;grid-template-columns:repeat(4,minmax(38px,1fr));gap:4px;min-width:150px}.pq-seg{position:relative;display:grid;justify-items:center;gap:0;background:var(--desk-2);border:1px solid var(--edge);border-radius:8px;padding:3px 2px 6px;overflow:hidden}.pq-seg b{font:700 14px var(--head);color:var(--text)}.pq-seg small{font:500 10px var(--mono);color:var(--dim)}.pq-seg i{position:absolute;left:0;bottom:0;height:3px;background:var(--mint)}.pq-seg.none{opacity:.45}.pq-dn{display:block;margin-top:4px;color:var(--dim);font-size:12px}.pq-learn{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.pq-lc{display:grid;gap:6px;align-content:start;background:var(--paper);color:var(--ink);border-radius:16px;padding:14px 16px}.pq-lc b{font:700 16px var(--head)}.pq-lc span{color:var(--ink-2);font-size:14px}.pq-lc div{margin-top:4px}.pq-grid{display:grid;grid-template-columns:minmax(190px,1.15fr) repeat(2,minmax(0,1fr));gap:10px}.pq-gh{font:500 11px var(--mono);text-transform:uppercase;letter-spacing:.06em;color:var(--dim);padding:0 4px}.pq-lh{display:grid;gap:3px;align-content:start;background:var(--desk-3);border:1px solid var(--edge);border-radius:14px;padding:12px 14px}.pq-lh b{font:700 16px var(--head);color:var(--lamp)}.pq-lh b small{font:500 11px var(--mono);color:var(--dim);margin-right:4px}.pq-lh span{color:var(--dim);font-size:13px;line-height:1.45}.pq-cell{display:grid;gap:5px;align-content:start;background:var(--paper);color:var(--ink);border-radius:14px;padding:12px 14px;min-width:0}.pq-cp{display:none;font:500 11px var(--mono);text-transform:uppercase;letter-spacing:.05em;color:var(--ink-2)}.pq-cell b{font:700 15px var(--head)}.pq-cell b small{font:500 12.5px var(--body);color:var(--ink-2)}.pq-cell .pq-bar{background:var(--tint)}.pq-cell .pq-dn{color:var(--ink-2);margin:0}.pq-no{color:var(--mute);font-size:14px}.pq-cell:has(.pq-no){background:var(--desk-2);border:1px dashed var(--edge)}.pq-cell:has(.pq-no) .pq-no{color:var(--dim)}.pq-cb{display:flex;flex-wrap:wrap;gap:6px 12px;align-items:center;margin-top:4px}.pq-cell .btn.ghost{color:var(--ink);border-color:var(--line2)}.pq-cell .btn{padding:6px 14px;font-size:13.5px}.pq-sheetl{color:var(--coral-ink);font-size:13.5px;font-weight:600;text-decoration:none}.pq-sheetl:hover{text-decoration:underline}.pq-lk{font-size:13.5px;color:var(--ink-2)}.pq-papers{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 14px}.pq-pp{border:1px solid var(--edge);background:var(--desk-3);border-radius:999px;padding:6px 14px;font:500 13.5px var(--body);color:var(--dim);text-decoration:none}.pq-pp small{font:500 11px var(--mono);margin-left:4px}.pq-pp.off{opacity:.55}.pq-pp[aria-current]{background:var(--navy);color:var(--on-navy);border-color:var(--navy);font-weight:700}.pq-lv span{font-size:12.5px}.pq-sbar{display:flex;flex-wrap:wrap;align-items:center;gap:10px 14px;margin:0 0 14px}.pq-sbar small{color:var(--dim)}.pq-sheet{background:#fff;color:#000;border-radius:14px;padding:26px 30px;margin:0 0 20px}.pq-sheet header{border-bottom:2px solid #000;padding-bottom:8px;margin-bottom:14px}.pq-sl{font:600 14px var(--head);margin:0}.pq-ss{font-size:13px;color:#444;margin:3px 0 0}.pq-sqs{list-style:none;margin:0;padding:0}.pq-sq{display:grid;grid-template-columns:2.2em minmax(0,1fr) auto;gap:0 6px;padding:10px 0;border-bottom:1px solid #ddd;break-inside:avoid;page-break-inside:avoid}.pq-sn{font-weight:700}.pq-sm{font:600 13px var(--mono);white-space:nowrap}.pq-sb{min-width:0;font-size:16px;line-height:1.6;overflow-wrap:break-word}.pq-sb p{margin:.4em 0}.pq-sheet img{max-width:100%;height:auto}.pq-sheet .katex-display{overflow-x:auto;overflow-y:hidden}@media(max-width:900px){.pq-learn{grid-template-columns:minmax(0,1fr)}.pq-grid{grid-template-columns:minmax(0,1fr)}.pq-gh{display:none}.pq-lh{margin-top:8px}.pq-cp{display:block}.pq-tbl,.pq-tbl tbody,.pq-tbl tr,.pq-tbl td{display:block;width:100%}.pq-tbl thead{display:none}.pq-tbl tr{padding:10px 12px;border-bottom:1px solid var(--edge);display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:8px 12px}.pq-tbl td{padding:0;border:0}.pq-tbl td:first-child,.pq-tbl td[data-l="Practice"]{grid-column:1/-1}.pq-tbl td[data-l]:not(:first-child)::before{content:attr(data-l);display:block;font:500 10.5px var(--mono);text-transform:uppercase;color:var(--dim);margin-bottom:3px}.pq-go{grid-column:1/-1;text-align:left}.pq-segs{min-width:0}.pq-sheet{padding:16px 14px}}@media print{@page{margin:16mm}html.pq-sheetpage,html.pq-sheetpage body{background:#fff!important;color:#000!important}.pq-noprint,.skip,header.site,footer.site,.crumbs,.ws-side,.ws-tree,.ws-mob,.bk-fab,.bk-panel,.pq-hero,.pq-levels,.pq-papers,.pq-back,.srch,#pqMsg{display:none!important}.ws{display:block!important}.ws-main,.bk-open .ws-main{margin:0!important;max-width:none!important}.ws-main .wrap,.pq .wrap,.section{max-width:none!important;padding:0!important;margin:0!important}.pq-sheet{background:#fff;color:#000;border-radius:0;padding:0;margin:0}.pq-sheet *{color:#000!important}.pq-sq{break-inside:avoid;page-break-inside:avoid}}/* branded question-set PDF button (topic grid + questions view) */.pq-dlb{font-size:13px;padding:5px 12px}.pq-dlb:disabled{opacity:.6;cursor:progress}.pq-dl .pq-dlb{font-size:14px;padding:7px 14px}#pqMsg a{color:inherit;font-weight:600;text-decoration:underline}/* level colours (same as the PDFs): Foundation green, Core blue, Exam amber, Challenge red */[data-t="1"]{--lv:var(--lv-f)}[data-t="2"]{--lv:var(--lv-c)}[data-t="3"]{--lv:var(--lv-e)}[data-t="4"]{--lv:var(--lv-x)}.pq-lh[data-t] b{color:var(--lv)}.pq-lh[data-t]{border-left:4px solid var(--lv)}.pq-lv[data-t] b{color:var(--lv)}.pq-lv[data-t][aria-current]{box-shadow:inset 0 0 0 2px var(--lv)}.pq-seg[data-t] i{background:var(--lv)}#pqApp{padding-bottom:72px}   /* room for the floating booklet button *//* one-page topic view (2026-10-20): resources row, level list in the sidebar, paper toggle + toolbar, then the questions */.pq-hero.pq-compact{padding-block:18px 0}.pq-hero.pq-compact .ac-hero,.pq-hero.pq-compact{padding-bottom:0}.pq-hero .lede:empty{display:none}.pq-hero.pq-compact h1{font-size:clamp(28px,3.6vw,42px);margin-bottom:.2em}.pq-hero.pq-compact .eyebrow{margin-bottom:8px}.pq-hero.pq-compact+section.section{padding-top:14px}.pq-seglv{list-style:none;margin:0;padding:0}.pq-lvi.off{opacity:.55}.pq-res{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:0 0 14px}.pq-resl{font:600 12px var(--body);text-transform:uppercase;letter-spacing:.14em;color:var(--ink-2);margin-right:4px}.pq-res .pq-pdf{font-size:14px;padding:8px 14px;border-radius:10px}.pq-lvbar{display:none}.pq-tb{display:flex;flex-wrap:wrap;align-items:center;gap:10px 14px;margin:0 0 16px;padding:10px 12px;background:var(--card);border:1px solid var(--line);border-radius:var(--rs);box-shadow:var(--sh1)}.pq-pap{display:flex;padding:3px;background:var(--tint);border-radius:10px;gap:2px}.pq-pb{padding:7px 14px;border-radius:8px;font:600 14px var(--body);color:var(--ink-2);text-decoration:none;white-space:nowrap}.pq-pb[aria-current]{background:var(--card);color:var(--ink);box-shadow:0 1px 2px rgba(27,42,74,.14),0 0 0 1px var(--line)}.pq-pb.off{opacity:.55}.pq-ph{font-size:13px;color:var(--ink-2)}.pq-tb .pq-dlb{font-size:14px;padding:8px 14px}.pq-tsp{flex:1 1 0}.pq-tp{font-size:13.5px;color:var(--ink-2);white-space:nowrap}.pq-tp b{color:var(--ink)}.pq-tb .pq-bar{width:90px;height:6px;flex:none;grid-column:auto}.pq-filt{position:relative;background:none;border:0;box-shadow:none;padding:0;margin:0}.pq-filt summary{display:inline-flex;font:600 13.5px var(--body);letter-spacing:0;padding:7px 12px;border-radius:8px;box-shadow:0 0 0 1px var(--line2);background:var(--card);color:var(--ink)}.pq-filt summary:after{content:"▾";margin-left:6px;color:var(--ink-2);font-size:12px}.pq-filt[open] summary:after{content:"▴"}.pq-filt .pq-filters{position:absolute;right:0;top:calc(100% + 6px);z-index:20;width:min(560px,86vw);margin:0;padding:12px;background:var(--card);border:1px solid var(--line);border-radius:var(--rs);box-shadow:var(--sh2)}.pq-none-here{display:grid;gap:10px;justify-items:start;color:var(--ink-2)}.pq-none-here p{margin:0}@media(max-width:899px){.pq-lvbar{display:block;position:sticky;top:calc(66px + env(safe-area-inset-top,0px) + 54px);z-index:25;margin:0 -16px 12px;padding:8px 16px;background:color-mix(in srgb,var(--bg) 97%,transparent);border-bottom:1px solid var(--line)}.pq-seglv{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:4px;padding:3px;background:var(--tint);border-radius:10px}.pq-seglv .pq-lvi{display:grid;gap:0;text-align:center;padding:6px 2px;border-radius:8px;text-decoration:none;color:var(--ink-2);border-bottom:3px solid var(--lv)}.pq-seglv .pq-lvi b{font:700 12.5px var(--head);color:var(--ink)}.pq-seglv .pq-lvi span{font-size:11px;color:var(--ink-2)}.pq-seglv .pq-lvi[aria-current]{background:var(--card);box-shadow:0 1px 2px rgba(27,42,74,.14),0 0 0 1px var(--line)}.pq-tsp{display:none}.pq-ph{display:none}.pq-tp{flex:1 1 100%}.pq-filt .pq-filters{position:static;width:auto;margin-top:8px}.pq-filt{flex:1 1 100%}}/* CLS fix (lean sweep): reserve the table's height while topics load, so the footer never jumps into view. */.pq-skel{min-height:1500px}.pq-skel i{display:block;height:56px;margin:0 0 10px;border-radius:12px;background:linear-gradient(90deg,var(--desk-2) 25%,var(--tint) 50%,var(--desk-2) 75%);background-size:200% 100%;animation:pqsk 1.4s linear infinite}@keyframes pqsk{to{background-position:-200% 0}}@media(max-width:700px){.pq-skel i{height:150px}.pq-skel i:nth-of-type(n+7){display:none}}@media(prefers-reduced-motion:reduce){.pq-skel i{animation:none}}.pq-freeb{display:inline-block;margin-left:6px;font:700 10.5px var(--body);letter-spacing:.06em;text-transform:uppercase;color:var(--ok-t,#2f7d4f);background:var(--ok-bg,#eaf6ee);border:1px solid var(--ok-b,#bfe0cb);border-radius:999px;padding:1px 8px;vertical-align:middle}@media(min-width:701px){.pq-tbl th small{display:block;text-transform:none;letter-spacing:0;font-size:10px;margin-top:2px}}/* Worksheet Studio "three doors" ways-in block (tools/build.py studio_doors()). Static links, light and dark via site tokens. */.wd{--wd-sca:#1f5c46;--wd-scs:rgba(31,92,70,.09);display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin:26px 0 0}:root[data-theme="dark"] .wd{--wd-sca:#5fc49b;--wd-scs:rgba(95,196,155,.14)}.wd-door{display:flex;flex-direction:column;gap:14px;padding:26px 24px 22px;border-radius:16px;background:var(--card);box-shadow:0 0 0 1px var(--line),var(--sh1);text-align:left;min-width:0}.wd-door:hover{box-shadow:0 0 0 1px var(--line2),var(--sh2)}.wd-door h2{font-size:20px;line-height:1.2;display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin:0}.wd-who{margin:0;color:var(--dim);font-size:15px;line-height:1.5;flex:1}.wd-who b{color:var(--text);font-weight:600}.wd-ico{display:grid;place-items:center;width:48px;height:48px;border-radius:13px;background:var(--gold-t);color:var(--lamp);flex:none}.wd-ico.green{background:var(--wd-scs);color:var(--wd-sca)}.wd-acts{display:flex;flex-direction:column;gap:12px;align-items:stretch}.wd-acts .btn{width:100%;white-space:normal;text-align:center}.wd-link{font:600 13.5px var(--body);color:var(--lamp);text-decoration:none;text-align:center}.wd-link:hover{text-decoration:underline}.wd-fine{font-size:12.5px;color:var(--mute);text-align:center}.wd-g{display:grid;place-items:center;width:22px;height:22px;border-radius:50%;background:#fff}.wd-badge{display:inline-block;font:700 11px var(--body);letter-spacing:.04em;text-transform:uppercase;color:var(--lamp);background:var(--gold-t);border-radius:99px;padding:3px 9px}.wd-extra{font-size:13.5px;color:var(--mute);margin:18px 0 0}.wd-extra a{color:var(--lamp);font-weight:600;text-decoration:none}.wd-extra a:hover{text-decoration:underline}.wd-extra .btn{margin-left:10px}@media(max-width:900px){.wd{grid-template-columns:1fr;gap:14px}.wd-door{padding:22px 20px 20px}}/* Worksheet Studio guided tour (/schools/worksheet-studio/tour/): progress row + alternating step / screenshot rows. */html{scroll-behavior:smooth}.tr-nav{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg) 92%,transparent);backdrop-filter:blur(8px);border-block:1px solid var(--line)}.tr-nav ol{list-style:none;margin:0;padding:8px 0;display:flex;gap:6px;overflow-x:auto;scrollbar-width:none}.tr-nav li{flex:1 0 auto}.tr-nav a{display:flex;align-items:center;justify-content:center;gap:8px;padding:6px 12px;border-radius:99px;text-decoration:none;color:var(--dim);font:600 13.5px var(--body);white-space:nowrap}.tr-nav a b{display:grid;place-items:center;width:22px;height:22px;border-radius:50%;background:var(--gold-t);color:var(--ink);font-size:12px}.tr-nav a:hover,.tr-nav a.on{color:var(--ink);background:var(--hov)}.tr-nav a.on b{background:var(--navy);color:var(--on-navy)}section.tr-step{padding-block:56px;scroll-margin-top:56px}section.tr-step:nth-of-type(even){background:color-mix(in srgb,var(--tint) 60%,transparent)}.tr-grid{display:grid;grid-template-columns:minmax(0,5fr) minmax(0,7fr);gap:48px;align-items:center}.tr-step:nth-of-type(even) .tr-txt{order:2}.tr-txt h2{margin:0 0 12px}.tr-txt p{color:var(--dim);margin:0 0 14px;max-width:44ch}.tr-txt .eyebrow{margin-bottom:10px}.tr-next{margin-top:18px!important}.tr-fig{display:grid;gap:18px;min-width:0}.tr-frame{border-radius:12px;background:#fff;box-shadow:0 0 0 1px var(--line2),var(--sh2);overflow:hidden;min-width:0}.tr-bar{display:flex;gap:6px;padding:9px 12px;background:#f3f4f7;border-bottom:1px solid #e2e4ea}.tr-bar i{width:9px;height:9px;border-radius:50%;background:#cfd3dc}.tr-frame img{display:block;width:100%;height:auto}:root[data-theme="dark"] .tr-frame{box-shadow:0 0 0 1px var(--line3),var(--sh2)}@media(max-width:900px){.tr-grid{grid-template-columns:1fr;gap:24px}.tr-step:nth-of-type(even) .tr-txt{order:0}section.tr-step{padding-block:40px}}.tr-hero{padding-block:30px 34px}.tr-hero h1{font-size:clamp(32px,4.2vw,46px);max-width:22ch}.tr-txt h2{font-size:clamp(24px,2.6vw,30px)}.tr-nav ol{scroll-snap-type:x proximity}.tr-nav li{scroll-snap-align:center}.sx{position:relative;margin-top:8px}.sx-track{display:flex;gap:18px;overflow-x:auto;scroll-snap-type:x mandatory;scrollbar-width:none;-webkit-overflow-scrolling:touch;padding:4px 2px 8px}.sx-track::-webkit-scrollbar{display:none}.sx-slide{flex:0 0 100%;scroll-snap-align:start;margin:0;display:grid;gap:18px;align-items:center;border:1px solid var(--band-line);border-top:3px solid var(--frame);border-radius:14px;background:var(--card);padding:16px;grid-template-columns:1fr}@media(min-width:900px){.sx-slide{grid-template-columns:minmax(0,1.5fr) minmax(0,1fr);padding:22px;gap:30px}}.sx-slide img{width:100%;height:auto;border-radius:10px;border:1px solid var(--line2);box-shadow:var(--sh1);display:block}.sx-slide h3{font-size:clamp(20px,2.2vw,26px);margin:0 0 8px}.sx-slide p{color:var(--dim);margin:0 0 10px}.sx-n{display:inline-grid;place-items:center;width:30px;height:30px;border-radius:50%;background:var(--frame);color:var(--frame-ink);font:700 14px var(--body);margin-bottom:10px}.sx-slide .tickrow{grid-template-columns:1fr;gap:6px}.sx-nav{position:absolute;top:42%;z-index:2;width:42px;height:42px;border-radius:50%;border:1px solid var(--line2);background:var(--card);color:var(--ink);font-size:24px;cursor:pointer;box-shadow:var(--sh1);display:none}@media(min-width:900px){.sx-nav{display:block}}.sx-nav.prev{left:-14px}.sx-nav.next{right:-14px}.sx-dots{display:flex;justify-content:center;gap:10px;margin-top:6px}.sx-dots button{width:11px;height:11px;border-radius:50%;border:0;padding:0;background:var(--line3);cursor:pointer}.sx-dots button[aria-current=true]{background:var(--frame);transform:scale(1.2)}.trust3{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}.trust3 a.tile{text-decoration:none;color:inherit}.trust3 a.tile:hover{background:var(--hov)}/* course workspace: sidebar + (topic tree) + main column (tools/course_nav.py) */.ws{display:grid;grid-template-columns:250px minmax(0,1fr);max-width:1440px;margin:0 auto}.ws.three{grid-template-columns:250px 260px minmax(0,1fr)}.ws-side,.ws-tree{position:sticky;top:calc(66px + env(safe-area-inset-top,0px));align-self:start;max-height:calc(100vh - 66px);overflow:auto;border-right:1px solid var(--edge);padding:18px 12px 28px max(12px,env(safe-area-inset-left,0px));scrollbar-width:thin}.ws-tree{background:color-mix(in srgb,var(--desk-2) 85%,transparent);padding-left:12px}.ws-main{min-width:0}.ws-main>.crumbs,.ws-main .wrap{max-width:1040px}.ws-switch{border:1px solid var(--edge);border-radius:12px;background:var(--desk-3)}.ws-switch summary{list-style:none;cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:8px;padding:10px 12px}.ws-switch summary::-webkit-details-marker{display:none}.ws-switch summary:after{content:"▾";color:var(--dim)}.ws-switch small{display:block;color:var(--dim);font-size:12px}.ws-switch b{font:700 15px var(--head);letter-spacing:-.02em}.ws-switch ul{list-style:none;margin:0;padding:0 6px 8px}.ws-switch li a{display:block;padding:6px 8px;border-radius:8px;color:var(--text);text-decoration:none;font-size:14px}.ws-switch li a:hover,.ws-switch li a[aria-current]{background:var(--gold-t);color:var(--lamp)}.ws-h{font:500 11.5px var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--dim);margin:18px 8px 6px}.ws-list{list-style:none;margin:0;padding:0}.ws-list a{display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:10px;color:var(--text);text-decoration:none;font-size:14.5px;line-height:1.3}.ws-list a:hover{background:var(--hov)}.ws-list a[aria-current]{background:var(--gold-t);color:var(--lamp);font-weight:600}.ws-i{width:18px;text-align:center;opacity:.85;flex:none}.ws-r{margin-left:auto;font:500 11px var(--mono);color:var(--bad-t);white-space:nowrap}.ws-r.free{color:var(--ok-t)}.ws-r.own{color:var(--lamp)}.ws-unlock{margin:18px 4px 0;display:grid;gap:6px;background:linear-gradient(160deg,var(--gold-t),var(--gold-t));border:1px solid var(--gold-b);border-radius:14px;padding:12px;font-size:13.5px;color:var(--dim)}.ws-unlock b{color:var(--text);font:700 14.5px var(--head)}.ws-unlock .btn{justify-self:start;padding:7px 13px;font-size:13.5px}.ws-unlock small{font-size:12px}.btn.coral{background:linear-gradient(var(--btn1),var(--btn2));color:var(--on-navy)}.ws-th{font:700 14px var(--head);margin:4px 6px 10px}.ws-tree details{border:1px solid var(--edge);border-radius:12px;margin:0 0 8px;background:var(--desk-2);color:var(--text);padding:0}.ws-tree summary{list-style:none;cursor:pointer;padding:10px 12px;font:600 13.5px var(--head);display:flex;justify-content:space-between;gap:8px;color:var(--text)}.ws-tree summary::-webkit-details-marker{display:none}.ws-tree summary small{font:500 11px var(--mono);color:var(--dim)}.ws-tree ol{list-style:none;margin:0;padding:0 8px 8px}.ws-tree li a{display:flex;gap:8px;align-items:center;padding:6px 8px;border-radius:8px;color:var(--dim);text-decoration:none;font-size:13.5px;line-height:1.3}.ws-tree li a:before{content:"";width:8px;height:8px;border-radius:50%;border:1.5px solid currentColor;flex:none;opacity:.7}.ws-tree li a:hover{color:var(--text)}.ws-tree li a[aria-current]{background:var(--gold-t);color:var(--lamp);font-weight:600}.ws-tree li a[aria-current]:before{background:var(--navy);border-color:var(--navy);opacity:1}.ws-mob{display:none}@media(max-width:1180px){.ws.three{grid-template-columns:250px minmax(0,1fr)}.ws.three>.ws-tree{display:none}.ws.three .ws-mob{display:flex}.ws.three .ws-mob .ws-drop:first-child{display:none}}@media(max-width:900px){.ws,.ws.three{grid-template-columns:minmax(0,1fr)}.ws-side,.ws.three>.ws-tree{display:none}.ws-mob,.ws.three .ws-mob{display:flex}.ws.three .ws-mob .ws-drop:first-child{display:block}}.ws-mob{gap:8px;flex-wrap:wrap;position:sticky;top:calc(66px + env(safe-area-inset-top,0px));z-index:30;background:color-mix(in srgb,var(--bg) 97%,transparent);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--edge);padding:8px max(16px,env(safe-area-inset-right,0px)) 8px max(16px,env(safe-area-inset-left,0px))}.ws-drop{background:none;color:var(--text);padding:0;border:0;margin:0}.ws-drop>summary{list-style:none;cursor:pointer;border:1px solid var(--edge);border-radius:999px;padding:7px 13px;font:600 13.5px var(--body);background:var(--desk-3);display:inline-block}.ws-drop>summary::-webkit-details-marker{display:none}.ws-drop[open]>summary{border-color:var(--lamp);color:var(--lamp)}.ws-drop>nav{position:absolute;left:0;right:0;top:100%;max-height:70vh;overflow:auto;background:var(--desk);border-bottom:1px solid var(--edge);padding:12px max(16px,env(safe-area-inset-right,0px)) 16px max(16px,env(safe-area-inset-left,0px));box-shadow:var(--sh1)}/* cheatsheet header and the matching paid notes */.cs-meta{display:flex;flex-wrap:wrap;align-items:center;gap:8px 16px;color:var(--dim);font-size:14px;margin:4px 0 14px}.cs-meta .av{width:32px;height:32px;border-radius:50%;background:#2b3a55;color:#fff;display:grid;place-items:center;font:700 12.5px var(--head)}.cs-meta b{color:var(--text)}.cs-acts{display:flex;flex-wrap:wrap;gap:8px}.cs-up{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:12px 16px;align-items:center;background:var(--desk-2);border:1px solid var(--gold-b);border-radius:16px;padding:14px 16px;margin:18px 0}.cs-up b{display:block;font:700 16px var(--head);color:var(--text)}.cs-up span{color:var(--dim);font-size:14px}@media(max-width:640px){.cs-up{grid-template-columns:minmax(0,1fr)}.cs-up .btn{justify-self:start}}.cs-dlbar{display:none}@media(max-width:900px){.cs-dlbar{display:flex;gap:8px;position:fixed;left:0;right:0;bottom:0;z-index:35;background:color-mix(in srgb,var(--bg) 97%,transparent);border-top:1px solid var(--edge);padding:10px max(16px,env(safe-area-inset-right,0px)) calc(10px + env(safe-area-inset-bottom,0px)) max(16px,env(safe-area-inset-left,0px))}.cs-dlbar .btn{flex:1;justify-content:center;padding:10px 12px;font-size:14px}body:has(.cs-dlbar) footer.site{padding-bottom:80px}}/* keep the site's FAQ <details> styling out of the workspace menus */.ws details{background:none;color:var(--text);padding:0;margin:0;border-radius:0;border:0;box-shadow:none}.ws .ws-switch{border-radius:12px;background:var(--card);border:1px solid var(--edge)}.ws .ws-tree details{border-radius:12px;margin:0 0 8px;background:var(--card);border:1px solid var(--edge)}.ws summary{color:var(--text);font-size:inherit;letter-spacing:normal}.ws-switch summary:after{content:"▾";color:var(--dim);font-size:13px}.ws-switch[open] summary:after{content:"▴"}.ws-tree summary:after,.ws-drop>summary:after{content:none}.ws-drop>summary{color:var(--text)}.ws.ws-none{grid-template-columns:minmax(0,1fr)}.ws.ws-none>.ws-side,.ws.ws-none .ws-mob{display:none}.ws details summary:after,.ws details[open] summary:after{content:none}.ws .ws-switch summary:after{content:"▾";color:var(--dim);font-size:13px}.ws .ws-switch[open] summary:after{content:"▴"}.ws .ws-tree details>summary:before{content:"▸";color:var(--dim);margin-right:6px}.ws .ws-tree details[open]>summary:before{content:"▾"}.ws .ws-tree summary{justify-content:flex-start}.ws .ws-tree summary small{margin-left:auto}.ws-unlock[hidden],.cs-up[hidden],[data-unlock][hidden]{display:none}/* floating formula booklet: button, side panel, embedded view (?embed=1) */.bk-fab{position:fixed;right:max(18px,env(safe-area-inset-right,0px));bottom:calc(18px + env(safe-area-inset-bottom,0px));z-index:60;display:inline-flex;align-items:center;gap:8px;background:var(--navy);color:var(--on-navy);border:0;border-radius:999px;padding:12px 18px;font:600 14.5px var(--body);box-shadow:var(--sh1);cursor:pointer}.bk-fab span{font:700 18px var(--head);line-height:1}.bk-fab[hidden]{display:none}.bk-open .bk-fab{background:var(--desk-3);color:var(--lamp);border:1px solid var(--lamp)}.bk-panel{position:fixed;top:calc(66px + env(safe-area-inset-top,0px));right:0;bottom:0;z-index:55;width:min(560px,100%);display:flex;flex-direction:column;background:var(--desk);border-left:1px solid var(--edge);box-shadow:var(--sh1);animation:bkin .25s ease-out}.bk-panel[hidden]{display:none}@keyframes bkin{from{transform:translateX(30px);opacity:0}to{transform:none;opacity:1}}@media (prefers-reduced-motion:reduce){.bk-panel{animation:none}}.bk-bar{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:10px 14px;border-bottom:1px solid var(--edge)}.bk-bar b{font:700 15px var(--head)}.bk-bar span{display:flex;gap:6px}.bk-bar .btn{padding:7px 12px;font-size:13.5px}.bk-panel iframe{flex:1;width:100%;border:0;background:var(--desk)}@media(min-width:1181px){.bk-open .ws-main{margin-right:min(560px,40vw)}}@media(max-width:900px){.bk-panel{width:100%}.bk-fab{bottom:calc(76px + env(safe-area-inset-bottom,0px))}}.embed header.site,.embed footer.site,.embed .crumbs,.embed .skip,.embed .bk-fab,.embed .burger{display:none!important}.embed body{background-image:none}.embed .hero{padding-block:18px 10px}@media(max-width:640px){.bk-fab{padding:0;width:50px;height:50px;justify-content:center}.bk-fab b{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}.bk-fab span{font-size:22px}}/* simplified sidebar (2026-10-20): course switcher, Topics (current topic opens its levels), More, small unlock box */.ws-all{margin:0 8px 6px;font-size:13.5px}.ws-all a{color:var(--ink-2);text-decoration:none;font-weight:600}.ws-all a:hover{color:var(--ink);text-decoration:underline}.ws-all a[aria-current]{color:var(--lamp)}.ws-topics{list-style:none;margin:0;padding:0;max-height:min(52vh,460px);overflow:auto;scrollbar-width:thin;border-block:1px solid var(--line)}.ws-topics>li>a{display:block;padding:6px 10px;border-radius:8px;color:var(--ink);text-decoration:none;font-size:14px;line-height:1.3}.ws-topics>li>a:hover{background:var(--hov)}.ws-topics>li>a[aria-current]{background:var(--gold-t);color:var(--lamp);font-weight:700}.ws-topics .pq-sidelv{display:grid;gap:3px;list-style:none;margin:4px 0 8px 10px;padding:0}.ws-topics .pq-sidelv .pq-lvi{display:flex;justify-content:space-between;align-items:center;gap:8px;padding:6px 8px 6px 10px;border-radius:8px;border-left:4px solid var(--lv);background:var(--card);box-shadow:0 0 0 1px var(--line);color:var(--ink);text-decoration:none;font-size:13.5px}.ws-topics .pq-sidelv .pq-lvi b{font:700 13.5px var(--head);color:var(--ink)}.ws-topics .pq-sidelv .pq-lvi span{font-size:12px;color:var(--ink-2);white-space:nowrap}.ws-topics .pq-sidelv .pq-lvi[aria-current]{background:color-mix(in srgb,var(--lv) 12%,var(--card));box-shadow:0 0 0 2px var(--lv)}.ws-topics .pq-sidelv .pq-lvi[aria-current] b{color:var(--lv)}.ws-list a{padding:7px 10px;font-size:14.5px}.ws-unlock{display:flex;align-items:center;justify-content:space-between;gap:8px;flex-wrap:wrap;padding:10px 12px;font-size:13.5px}.ws-unlock span{font-weight:700;color:var(--ink)}.ws-unlock .btn{height:34px;min-height:34px;padding:0 12px;font-size:13px}.ws-drop .ws-topics{max-height:none;overflow:visible}.trustrow{list-style:none;margin:20px 0 0;padding:0;display:flex;flex-wrap:wrap;gap:8px 22px;color:var(--dim);font-size:14px}.trustrow li:before{content:"✓ ";color:var(--ok-t)}/* FAQ accordions inside the course workspace (the .ws details reset above flattened them) */.ws .faqwrap details{background:var(--card);border:1px solid var(--edge);border-radius:14px;padding:16px 20px;margin:0 0 10px;box-shadow:var(--sh1)}.ws .faqwrap summary{display:flex;justify-content:space-between;gap:14px;font:600 16.5px var(--head);letter-spacing:-.02em;color:var(--text);list-style:none}.ws .faqwrap summary::-webkit-details-marker{display:none}.ws .faqwrap details summary:after{content:"+";color:var(--coral-ink);font-size:22px;line-height:1}.ws .faqwrap details[open] summary:after{content:"\2212"}.ws .faqwrap details p{margin:10px 0 0;color:var(--dim)}/* Formula booklet button (lean sweep): a slim tab on the right edge on desktop, a 44px icon on phones; never over content */@media(min-width:901px){.bk-fab{right:0;bottom:auto;top:50%;transform:translateY(-50%);border-radius:12px 0 0 12px;padding:14px 9px;writing-mode:vertical-rl;gap:6px;font-size:13.5px;box-shadow:var(--sh1)}.bk-fab span{writing-mode:horizontal-tb}.bk-open .bk-fab{right:min(560px,100%)}.ws-main{padding-right:26px}}@media(max-width:900px){.ws-main{padding-bottom:84px}}@media(max-width:640px){.bk-fab{width:44px;height:44px;right:12px}}/* Navy frame (owner picked option C, 2026-10-21; mockups ~/PhotonResourcesHQ/mockups/tone-options/): a navy lineunder the site header, navy table headers with light zebra rows in the library, pale blue bands for the coursesidebar, alternate sections and the footer. Named zz- so it loads after the other parts and wins. */:root{--frame:#1b2a4a;--frame-ink:#ffffff;--band:#f2f5fa;--band-line:#dfe5ef;--zebra:#f6f8fb}@media screen{:root[data-theme="dark"]{--frame:#2b3a5c;--frame-ink:#e8ecf3;--band:#131a28;--band-line:#263043;--zebra:rgba(255,255,255,.025)}}header.site{border-bottom:3px solid var(--frame)}.ws-side{background:var(--band);border-right:1px solid var(--band-line)}section.alt{background:var(--band);border-block-color:var(--band-line)}footer.site{background:var(--band);border-top:3px solid var(--frame)}.pq-tbl th,.pl-th,.db-tbl th{background:var(--frame);color:var(--frame-ink)}.pq-tbl tbody tr:nth-child(even){background:var(--zebra)}.pq-tbl tbody tr:nth-child(even) td{background:transparent}/* Practice questions (owner, 2026-10-21: "between question 1 and 2 it's just white"): each question is a framed cardwith a pale blue header strip and a navy edge. .pq-card.got keeps its own border colour (higher specificity). */.pq-card{border-color:var(--band-line);box-shadow:0 1px 2px rgba(27,42,74,.05),0 8px 20px rgba(27,42,74,.06);margin-bottom:22px}.pq-ch{background:var(--band);border-bottom:1px solid var(--band-line);box-shadow:inset 4px 0 0 var(--frame);padding-bottom:12px}.pq-q{padding-top:12px}/* Course sidebar, "level dots" (owner picked option 2, 2026-10-21): topic badges + the four level colours,More links with gold icon tiles. Markup: tools/course_nav.py (_topic_inner, _icon). */.ws-topics>li>a{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:6px 8px}.ws-tl{display:flex;align-items:center;gap:10px;min-width:0}.ws-tn{min-width:0}.ws-b{flex:none;width:24px;height:24px;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;background:var(--card);border:1px solid var(--band-line);color:var(--navy-2,#24365e);font:700 11px var(--body);font-variant-numeric:tabular-nums}.ws-b.ws-bw{width:auto;min-width:30px;padding:0 6px;border-radius:12px}.ws-dots{display:flex;gap:3px;flex:none}.ws-dots i{width:6px;height:6px;border-radius:50%;opacity:.85}.ws-dots i:nth-child(1){background:var(--lv-f)}.ws-dots i:nth-child(2){background:var(--lv-c)}.ws-dots i:nth-child(3){background:var(--lv-e)}.ws-dots i:nth-child(4){background:var(--lv-x)}.ws-topics>li>a[aria-current]{background:var(--card);color:var(--ink);box-shadow:inset 3px 0 0 var(--gold),0 1px 2px rgba(27,42,74,.08)}.ws-topics>li>a[aria-current] .ws-b{background:var(--frame);color:var(--frame-ink);border-color:transparent}.ws-list{display:grid;gap:6px}.ws-list a{background:var(--card);border:1px solid var(--band-line);font-weight:500}.ws-list a:hover{border-color:var(--gold);background:var(--card)}.ws-list a[aria-current]{border-color:var(--gold)}.ws-ic{flex:none;width:28px;height:28px;border-radius:8px;background:var(--gold-t);color:var(--lamp);display:flex;align-items:center;justify-content:center}.ws-ic svg{width:17px;height:17px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}/* "NEW" badge for the IA & EE Coach menu item: the SOON badge, filled navy with gold text */.soon.new{background:var(--frame);border-color:var(--frame);color:#f2d38b;font-weight:600}