@font-face{font-family:Manrope;src:url('Manrope.ttf')}@font-face{font-family:Newsreader;src:url('Newsreader.ttf')}@font-face{font-family:IBM Plex Mono;src:url('IBMPlexMono-Regular.ttf')}@font-face{font-family:IBM Plex Mono;src:url('IBMPlexMono-SemiBold.ttf');font-weight:600}
:root{--bg:#071119;--panel:#0e1b24;--panel-2:#12242e;--panel-3:#172d37;--text:#f2efe8;--muted:#a7b0b8;--muted-2:#76858e;--line:#29404a;--line-2:#3b545f;--brass:#d3b36a;--brass-soft:#f1d792;--mint:#81d5b0;--cyan:#69b7c8;--red:#ed8b88;--rail:292px;--top:66px;--radius:14px;--shadow:0 24px 80px rgba(0,0,0,.24)}
*{box-sizing:border-box}html{scroll-behavior:auto;scroll-padding-top:88px}body{margin:0;background:var(--bg);color:var(--text);font-family:Manrope,Arial,sans-serif;font-size:16px;line-height:1.62;overflow-x:hidden}a{color:inherit}img{display:block;max-width:100%}button,input,select{font:inherit}.skip-link{position:fixed;z-index:1000;left:16px;top:-80px;padding:12px 18px;background:var(--text);color:var(--bg);border-radius:8px}.skip-link:focus{top:12px}
.topbar{position:fixed;z-index:80;inset:0 0 auto;display:flex;align-items:center;justify-content:space-between;height:var(--top);padding:0 22px;background:rgba(7,17,25,.96);border-bottom:1px solid var(--line);backdrop-filter:blur(16px)}.book-id{display:flex;align-items:center;gap:12px}.book-id>img{width:22px;height:22px;filter:invert(1)}.book-id span{display:grid}.book-id strong{font-size:13px;letter-spacing:.03em}.book-id small{color:var(--muted);font-size:10px}.top-actions{display:flex;align-items:center;gap:8px}.top-actions a,.top-actions button,.menu-button{display:flex;align-items:center;justify-content:center;gap:8px;min-height:42px;padding:0 14px;border:1px solid var(--line-2);border-radius:8px;background:var(--panel);color:var(--text);font-size:11px;font-weight:800;text-decoration:none;cursor:pointer}.top-actions a img,.menu-button img{width:16px;height:16px;filter:invert(1)}.top-actions button[aria-pressed=true]{border-color:var(--brass);background:#2a271d;color:var(--brass-soft)}.menu-button{display:none;width:44px;padding:0}.progress{position:fixed;z-index:90;left:0;right:0;top:var(--top);height:3px;background:#061017}.progress span{display:block;width:0;height:100%;background:var(--brass)}
.layout{padding-top:calc(var(--top) + 3px)}.rail{position:fixed;z-index:50;left:0;top:calc(var(--top) + 3px);bottom:0;width:var(--rail);display:flex;flex-direction:column;padding:20px 14px 18px;background:#08131b;border-right:1px solid var(--line);overflow-y:auto}.rail-brand{display:flex;align-items:center;gap:12px;padding:0 8px 18px;border-bottom:1px solid var(--line)}.rail-brand>span{display:grid;place-items:center;width:44px;height:44px;background:var(--text);color:var(--bg);border-radius:10px;font-family:Newsreader;font-size:19px}.rail-brand p{display:grid;margin:0}.rail-brand strong{font-family:Newsreader;font-size:19px}.rail-brand small{color:var(--muted);font-size:10px}.chapter-search,.glossary-search{display:flex;align-items:center;gap:8px;margin:14px 0;padding:0 11px;border:1px solid var(--line);border-radius:8px;background:var(--panel)}.chapter-search img,.glossary-search img{width:15px;height:15px;filter:invert(1);opacity:.7}.chapter-search input,.glossary-search input{width:100%;height:42px;border:0;outline:0;background:transparent;color:var(--text);font-size:12px}.rail nav{display:grid;gap:2px}.rail nav a{display:grid;grid-template-columns:18px 1fr;gap:10px;align-items:start;min-height:44px;padding:9px 10px;border-left:2px solid transparent;border-radius:0 8px 8px 0;color:var(--muted);text-decoration:none}.rail nav a img{width:16px;height:16px;margin-top:3px;filter:invert(1);opacity:.65}.rail nav a span{display:grid;font-size:11px;line-height:1.35}.rail nav a b{color:var(--brass);font:600 9px IBM Plex Mono}.rail nav a:hover,.rail nav a[aria-current=location]{background:var(--panel);border-left-color:var(--brass);color:var(--text)}.rail nav a[hidden]{display:none}.rail-note{display:grid;grid-template-columns:18px 1fr;gap:10px;margin-top:18px;padding:14px 8px;border-top:1px solid var(--line);color:var(--muted);font-size:10px;line-height:1.5}.rail-note img{width:16px;height:16px;filter:invert(1)}.rail-note p{margin:0}.rail-note strong{display:block;color:var(--text);font-size:11px}.mobile-picker{display:none}
main{margin-left:var(--rail)}.cover,.scope,.deep-questions,.chapter,footer{max-width:1480px;margin:0 auto;padding-left:64px;padding-right:64px}.cover{min-height:calc(100vh - var(--top));display:grid;grid-template-columns:minmax(0,1.05fr) minmax(470px,.95fr);gap:70px;align-items:center;padding-top:80px;padding-bottom:72px;border-bottom:1px solid var(--line)}.eyebrow{display:flex;align-items:center;gap:10px;margin:0 0 14px;color:var(--muted);font:600 10px IBM Plex Mono;letter-spacing:.1em;text-transform:uppercase}.eyebrow span{color:var(--brass)}h1,h2{font-family:Newsreader,Georgia,serif;font-weight:400;letter-spacing:-.025em}h1{max-width:700px;margin:0;font-size:clamp(72px,8vw,128px);line-height:.88}.cover-subtitle{max-width:650px;margin:28px 0 0;color:var(--brass-soft);font:600 15px IBM Plex Mono}.cover-lede{max-width:690px;margin:28px 0 0;color:#c9ced0;font-size:19px;line-height:1.65}.cover-actions{display:flex;gap:10px;margin-top:34px}.cover-actions a{display:flex;align-items:center;min-height:48px;padding:0 18px;border:1px solid var(--line-2);border-radius:8px;background:var(--panel);font-size:12px;font-weight:800;text-decoration:none}.cover-actions a:first-child{border-color:var(--brass);background:var(--brass);color:var(--bg)}.cover-visual{align-self:center}.cover-visual>img{border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.cover-visual dl{display:grid;grid-template-columns:repeat(3,1fr);margin:12px 0 0;border:1px solid var(--line);border-radius:10px;background:var(--panel)}.cover-visual dl div{padding:14px 16px;border-right:1px solid var(--line)}.cover-visual dl div:last-child{border-right:0}.cover-visual dt{font:600 20px IBM Plex Mono;color:var(--brass)}.cover-visual dd{margin:2px 0 0;color:var(--muted);font-size:10px}
.scope{display:grid;grid-template-columns:.8fr 1.15fr;gap:48px;padding-top:82px;padding-bottom:82px;border-bottom:1px solid var(--line)}.mini-label{margin:0 0 10px;color:var(--brass);font:600 9px IBM Plex Mono;letter-spacing:.08em;text-transform:uppercase}.scope h2,.deep-questions h2{margin:0;font-size:48px;line-height:1.04}.scope>p{margin:0;color:#c8ced1;font-size:17px}.study-modes{grid-column:1/-1;display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden}.study-modes article{display:grid;gap:7px;padding:22px;border-right:1px solid var(--line);background:var(--panel)}.study-modes article:last-child{border-right:0}.study-modes b{color:var(--brass-soft);font:600 18px IBM Plex Mono}.study-modes span{color:var(--muted);font-size:12px}.deep-questions{padding-top:92px;padding-bottom:92px;border-bottom:1px solid var(--line)}.deep-questions h2{max-width:900px;font-size:64px}.deep-questions ol{counter-reset:questions;display:grid;grid-template-columns:repeat(3,1fr);gap:1px;margin:42px 0 0;padding:1px;background:var(--line);border-radius:var(--radius);overflow:hidden}.deep-questions li{counter-increment:questions;display:grid;grid-template-columns:30px 1fr;gap:12px;min-height:126px;padding:22px;background:var(--panel);list-style:none;font-size:13px}.deep-questions li:before{content:counter(questions,decimal-leading-zero);color:var(--brass);font:600 10px IBM Plex Mono}
.chapter{padding-top:100px;padding-bottom:110px;border-bottom:1px solid var(--line);scroll-margin-top:84px}.chapter-head{position:relative;max-width:1040px;margin-bottom:34px}.chapter-head h2{max-width:1000px;margin:0;font-size:clamp(52px,5.5vw,82px);line-height:.98}.chapter-subtitle{max-width:900px;margin:22px 0 0;color:#c5cccf;font-size:18px;line-height:1.6}.fast-tag{position:absolute;right:0;top:0;display:inline-flex;align-items:center;height:28px;padding:0 9px;border:1px solid #5d5537;border-radius:6px;background:#29261c;color:var(--brass-soft);font:600 9px IBM Plex Mono;text-transform:uppercase}.thirty{display:grid;grid-template-columns:160px 1fr;gap:22px;align-items:start;margin:38px 0;padding:24px;border-top:1px solid var(--brass);border-bottom:1px solid var(--line);background:linear-gradient(90deg,#171b18,var(--panel))}.thirty span{color:var(--brass);font:600 10px IBM Plex Mono;text-transform:uppercase}.thirty p{max-width:1020px;margin:0;font-family:Newsreader;font-size:25px;line-height:1.4}.teaching-visual{margin:0 0 34px}.teaching-visual img{width:100%;border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.teaching-visual figcaption{padding:10px 2px;color:var(--muted-2);font-size:10px}.mechanics{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden}.mechanic{min-height:210px;padding:24px;border-right:1px solid var(--line);border-bottom:1px solid var(--line);background:var(--panel)}.mechanic:nth-child(3n){border-right:0}.mechanic:nth-last-child(-n+3){border-bottom:0}.mechanic h3{margin:0;color:var(--brass-soft);font-size:14px}.mechanic p{margin:14px 0 0;color:var(--muted);font-size:13px;line-height:1.7}.worked-builder{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:34px}.worked,.builder{padding:28px;border:1px solid var(--line);border-radius:var(--radius);background:var(--panel)}.worked{border-top-color:var(--brass)}.builder{border-top-color:var(--mint)}.worked h3,.builder h3{margin:0;font-family:Newsreader;font-size:30px;font-weight:400}.worked ol,.builder ul{display:grid;gap:10px;margin:22px 0 0;padding-left:22px;color:#c8ced0;font-size:13px}.worked li::marker{color:var(--brass);font:600 10px IBM Plex Mono}.builder li::marker{color:var(--mint)}
.system-proof{margin:34px 0 0;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;background:var(--panel);box-shadow:var(--shadow)}.system-proof picture{display:block;padding:12px 12px 0}.system-proof img{width:100%;border:1px solid var(--line);border-radius:9px 9px 0 0}.system-proof figcaption{display:grid;grid-template-columns:auto 1fr auto;gap:16px;align-items:center;padding:18px 20px}.system-proof figcaption span{color:var(--brass);font:600 9px IBM Plex Mono;text-transform:uppercase}.system-proof figcaption strong{font-size:13px}.system-proof figcaption small{max-width:480px;color:var(--muted);font-size:10px;text-align:right}.fluency-grid{display:grid;grid-template-columns:1fr 1fr;gap:1px;margin-top:34px;padding:1px;background:var(--line);border-radius:var(--radius);overflow:hidden}.fluency-grid article{min-height:230px;padding:26px;background:var(--panel)}.fluency-grid blockquote{margin:18px 0 0;color:var(--mint);font-family:Newsreader;font-size:23px;line-height:1.45}.fluency-grid p,.fluency-grid ul{margin:18px 0 0;color:var(--muted);font-size:13px}.fluency-grid ul{display:grid;gap:9px;padding-left:20px}.fluency-grid .avoid li::marker{color:var(--red)}.knowledge-check{margin-top:32px;border:1px solid #625a3a;border-radius:var(--radius);background:#181811}.knowledge-check summary{display:grid;grid-template-columns:170px 1fr;gap:20px;align-items:center;min-height:74px;padding:18px 22px;cursor:pointer;list-style:none;font-family:Newsreader;font-size:20px}.knowledge-check summary::-webkit-details-marker{display:none}.knowledge-check summary span{color:var(--brass);font:600 9px IBM Plex Mono;text-transform:uppercase}.knowledge-check p{margin:0;padding:20px 22px;border-top:1px solid #625a3a;color:#d7d1bf}.chapter-sources{margin-top:38px}.source-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}.source-card{display:grid;align-content:start;min-height:156px;padding:18px;border:1px solid var(--line);border-radius:10px;background:var(--panel);text-decoration:none}.source-card:hover{border-color:var(--brass)}.source-card>span{color:var(--mint);font:600 9px IBM Plex Mono}.source-card strong{margin-top:12px;font-size:12px;line-height:1.45}.source-card small{margin-top:8px;color:var(--muted);font-size:10px;line-height:1.5}
.glossary-search{max-width:560px;margin:0 0 28px}.glossary dl{display:grid;grid-template-columns:repeat(2,1fr);gap:1px;margin:0;padding:1px;background:var(--line);border-radius:var(--radius);overflow:hidden}.glossary dl article{display:grid;grid-template-columns:150px 1fr;gap:18px;min-height:125px;padding:22px;background:var(--panel)}.glossary dl article[hidden]{display:none}.glossary dt{color:var(--brass-soft);font-weight:800}.glossary dd{margin:0;color:var(--muted);font-size:12px}.source-library{grid-template-columns:repeat(4,1fr)}footer{display:grid;grid-template-columns:auto 1fr auto;gap:26px;align-items:center;padding-top:48px;padding-bottom:48px;color:var(--muted);font-size:11px}footer strong{color:var(--text);font-family:Newsreader;font-size:18px}footer p{margin:0}footer a{color:var(--brass)}
body.fast-only .chapter[data-fast=false]{display:none}body.fast-only .rail nav a:not([data-nav=one-transaction]):not([data-nav=markets-people]):not([data-nav=money-time]):not([data-nav=instrument-contracts]):not([data-nav=price-language]):not([data-nav=orders-fills]):not([data-nav=leverage-risk]):not([data-nav=post-trade]):not([data-nav=domain-architecture]):not([data-nav=testing-roadmap]){opacity:.3}
:focus-visible{outline:2px solid var(--brass);outline-offset:3px}@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}
@media(max-width:1120px){:root{--rail:250px}.cover,.scope,.deep-questions,.chapter,footer{padding-left:38px;padding-right:38px}.cover{grid-template-columns:1fr;gap:42px}.cover-visual{max-width:900px}.mechanics{grid-template-columns:repeat(2,1fr)}.mechanic:nth-child(3n){border-right:1px solid var(--line)}.mechanic:nth-child(2n){border-right:0}.mechanic:nth-last-child(-n+3){border-bottom:1px solid var(--line)}.mechanic:nth-last-child(-n+2){border-bottom:0}.source-grid{grid-template-columns:repeat(2,1fr)}.source-library{grid-template-columns:repeat(3,1fr)}.deep-questions ol{grid-template-columns:repeat(2,1fr)}}
@media(max-width:860px){:root{--top:62px}.topbar{padding:0 12px}.menu-button{display:flex}.book-id{margin-right:auto;margin-left:10px}.book-id small{display:none}.top-actions button{display:none}.rail{transform:translateX(-102%);width:min(86vw,330px);transition:transform .2s ease;box-shadow:var(--shadow)}.rail.open{transform:translateX(0)}main{margin-left:0}.mobile-picker{position:sticky;z-index:40;top:calc(var(--top) + 3px);display:grid;grid-template-columns:auto minmax(0,1fr);gap:12px;align-items:center;padding:9px 14px;background:#08131b;border-bottom:1px solid var(--line)}.mobile-picker label{color:var(--muted);font:600 10px IBM Plex Mono}.mobile-picker select{width:100%;height:44px;padding:0 12px;border:1px solid var(--line-2);border-radius:8px;background:var(--panel);color:var(--text);font-size:12px}.cover,.scope,.deep-questions,.chapter,footer{padding-left:24px;padding-right:24px}.cover{padding-top:58px}.scope{grid-template-columns:1fr}.scope h2{font-size:46px}.study-modes{grid-template-columns:1fr}.study-modes article{border-right:0;border-bottom:1px solid var(--line)}.study-modes article:last-child{border-bottom:0}.deep-questions h2{font-size:54px}.worked-builder,.fluency-grid{grid-template-columns:1fr}.system-proof figcaption{grid-template-columns:1fr}.system-proof figcaption small{text-align:left}.source-library{grid-template-columns:repeat(2,1fr)}footer{grid-template-columns:1fr}}
@media(max-width:640px){body{font-size:16px}.top-actions a{width:44px;padding:0}.top-actions a img{margin:0}.top-actions a{font-size:0}.book-id strong{font-size:12px}.cover,.scope,.deep-questions,.chapter,footer{padding-left:14px;padding-right:14px}.cover{min-height:0;padding-top:46px;padding-bottom:56px}.cover h1{font-size:63px}.cover-subtitle{font-size:12px}.cover-lede{font-size:16px}.cover-actions{display:grid}.cover-actions a{justify-content:center}.cover-visual dl{grid-template-columns:1fr}.cover-visual dl div{border-right:0;border-bottom:1px solid var(--line)}.cover-visual dl div:last-child{border-bottom:0}.scope,.deep-questions{padding-top:64px;padding-bottom:64px}.scope h2,.deep-questions h2{font-size:43px}.deep-questions ol{grid-template-columns:1fr}.deep-questions li{min-height:96px}.chapter{padding-top:68px;padding-bottom:78px;scroll-margin-top:126px}.chapter-head h2{font-size:48px}.chapter-subtitle{font-size:16px}.fast-tag{position:static;margin-bottom:14px}.thirty{grid-template-columns:1fr;gap:8px;padding:18px}.thirty p{font-size:21px}.teaching-visual{margin-left:-14px;margin-right:-14px}.teaching-visual img{border-left:0;border-right:0;border-radius:0}.mechanics{grid-template-columns:1fr}.mechanic,.mechanic:nth-child(3n),.mechanic:nth-child(2n){min-height:0;border-right:0;border-bottom:1px solid var(--line)}.mechanic:last-child{border-bottom:0}.worked,.builder,.fluency-grid article{padding:20px}.worked h3,.builder h3{font-size:27px}.system-proof{margin-left:-14px;margin-right:-14px;border-left:0;border-right:0;border-radius:0}.system-proof picture{padding:6px 6px 0}.system-proof figcaption{padding:16px}.knowledge-check summary{grid-template-columns:1fr;gap:6px;font-size:18px}.source-grid,.source-library{grid-template-columns:1fr}.source-card{min-height:0}.glossary dl{grid-template-columns:1fr}.glossary dl article{grid-template-columns:1fr;gap:6px;min-height:0}.fluency-grid blockquote{font-size:21px}}
@media print{.topbar,.progress,.rail,.mobile-picker,.cover-actions,.chapter-search,.glossary-search{display:none!important}main{margin:0}.cover,.scope,.deep-questions,.chapter,footer{max-width:none;padding-left:0;padding-right:0}.chapter{break-before:page}.knowledge-check p{display:block}.source-card{break-inside:avoid}}

/* Issue #3: legibility and persistent theme controls. */
:root,
:root[data-theme="dark"]{
  color-scheme:dark;
  --rail:340px;
  --top:72px;
  --chrome-bg:rgba(7,17,25,.96);
  --rail-bg:#08131b;
  --progress-track:#061017;
  --text-body:#c9ced0;
  --accent-surface:#29261c;
  --accent-border:#5d5537;
  --teaching-wash:#171b18;
  --knowledge-bg:#181811;
  --knowledge-border:#625a3a;
  --knowledge-text:#d7d1bf;
  --icon-filter:invert(1);
}

:root[data-theme="light"]{
  color-scheme:light;
  --bg:#f5f2ea;
  --panel:#fffef9;
  --panel-2:#ece8dd;
  --panel-3:#e2ded3;
  --text:#13222a;
  --text-body:#293941;
  --muted:#53636b;
  --muted-2:#5f6e75;
  --line:#ccd3d2;
  --line-2:#9eacac;
  --brass:#765819;
  --brass-soft:#5d470f;
  --mint:#176a58;
  --cyan:#17677a;
  --red:#a23f3b;
  --chrome-bg:rgba(245,242,234,.96);
  --rail-bg:#ede9df;
  --progress-track:#d8dedb;
  --accent-surface:#f0e6cc;
  --accent-border:#9a813d;
  --teaching-wash:#eee8d8;
  --knowledge-bg:#fbf6e8;
  --knowledge-border:#a18a4b;
  --knowledge-text:#42391f;
  --icon-filter:none;
  --shadow:0 24px 80px rgba(15,28,34,.12);
}

@media(prefers-color-scheme:light){
  :root:not([data-theme]){
    color-scheme:light;
    --bg:#f5f2ea;
    --panel:#fffef9;
    --panel-2:#ece8dd;
    --panel-3:#e2ded3;
    --text:#13222a;
    --text-body:#293941;
    --muted:#53636b;
    --muted-2:#5f6e75;
    --line:#ccd3d2;
    --line-2:#9eacac;
    --brass:#765819;
    --brass-soft:#5d470f;
    --mint:#176a58;
    --cyan:#17677a;
    --red:#a23f3b;
    --chrome-bg:rgba(245,242,234,.96);
    --rail-bg:#ede9df;
    --progress-track:#d8dedb;
    --accent-surface:#f0e6cc;
    --accent-border:#9a813d;
    --teaching-wash:#eee8d8;
    --knowledge-bg:#fbf6e8;
    --knowledge-border:#a18a4b;
    --knowledge-text:#42391f;
    --icon-filter:none;
    --shadow:0 24px 80px rgba(15,28,34,.12);
  }
}

body{font-size:1.125rem;line-height:1.65;overflow-x:visible}
.topbar{min-height:var(--top);height:auto;background:var(--chrome-bg)}
.book-id>img,.top-actions a img,.menu-button img,.chapter-search img,.glossary-search img,.rail nav a img,.rail-note img{filter:var(--icon-filter)}
.book-id strong{font-size:.9375rem}.book-id small,.rail-brand small{font-size:.8125rem}
.top-actions a,.top-actions button,.menu-button{min-height:44px;font-size:.875rem}
.top-actions button.theme-toggle[aria-checked=true]{border-color:var(--line-2);background:var(--panel);color:var(--text)}
.theme-toggle{min-width:108px}.theme-icon{width:17px;height:17px;filter:var(--icon-filter)}
.theme-icon-sun{display:none}:root[data-theme="light"] .theme-icon-sun{display:block}:root[data-theme="light"] .theme-icon-moon{display:none}
.top-actions [data-fast-toggle][aria-pressed=true]{border-color:var(--brass);background:var(--accent-surface);color:var(--brass-soft)}
.progress{background:var(--progress-track)}
.rail{background:var(--rail-bg)}
.chapter-search input,.glossary-search input{min-height:48px;height:auto;font-size:1rem}
.rail nav a{grid-template-columns:20px 1fr;min-height:54px;padding:10px}
.rail nav a img{width:18px;height:18px}.rail nav a span{font-size:.875rem;line-height:1.45}.rail nav a b{font-size:.75rem;line-height:1.35}
.rail-note{font-size:.8125rem;line-height:1.6}.rail-note strong{font-size:.875rem}
.eyebrow{font-size:.8125rem;line-height:1.35}.cover-subtitle{font-size:1rem}.cover-lede{color:var(--text-body);font-size:1.25rem}
.cover-actions a{font-size:.9375rem}.cover-visual dd{font-size:.875rem;line-height:1.45}
.mini-label{font-size:.8125rem;line-height:1.35}.scope>p{color:var(--text-body);font-size:1.125rem}.study-modes span{font-size:1rem;line-height:1.55}
.deep-questions ol{grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr))}.deep-questions li{font-size:1rem;line-height:1.55}.deep-questions li:before{font-size:.75rem}
.chapter-subtitle{color:var(--text-body);font-size:1.25rem}.fast-tag{position:static;width:max-content;min-height:32px;height:auto;margin-bottom:16px;font-size:.75rem;line-height:1.35;border-color:var(--accent-border);background:var(--accent-surface)}
.thirty{background:linear-gradient(90deg,var(--teaching-wash),var(--panel))}.thirty span{font-size:.8125rem}.teaching-visual figcaption{color:var(--muted);font-size:.875rem;line-height:1.55}
.mechanics{grid-template-columns:repeat(auto-fit,minmax(min(100%,290px),1fr));gap:1px;padding:1px;border:0;background:var(--line)}
.mechanic,.mechanic:nth-child(3n),.mechanic:nth-child(2n),.mechanic:nth-last-child(-n+3),.mechanic:nth-last-child(-n+2){min-height:230px;border:0}
.mechanic h3{font-size:1.0625rem;line-height:1.4}.mechanic p{font-size:1rem;line-height:1.7}
.worked ol,.builder ul{color:var(--text-body);font-size:1rem;line-height:1.65}
.system-proof figcaption span{font-size:.75rem}.system-proof figcaption strong{font-size:1rem}.system-proof figcaption small{color:var(--muted);font-size:.875rem;line-height:1.55}
.fluency-grid p,.fluency-grid ul{font-size:1rem;line-height:1.65}.knowledge-check{border-color:var(--knowledge-border);background:var(--knowledge-bg)}
.knowledge-check summary span{font-size:.75rem}.knowledge-check p{padding:22px;border-color:var(--knowledge-border);color:var(--knowledge-text);font-size:1.125rem;line-height:1.65}
.source-grid,.source-library{grid-template-columns:repeat(auto-fit,minmax(min(100%,260px),1fr))}.source-card{min-height:190px;padding:20px}
.source-card>span{font-size:.8125rem}.source-card strong{font-size:1rem;line-height:1.45}.source-card small{font-size:.875rem;line-height:1.6}
.glossary dt{font-size:1.0625rem}.glossary dd{font-size:1rem;line-height:1.6}footer{font-size:.875rem;line-height:1.55}
.chapter-head h2,.source-card strong,.source-card small,.glossary dt,.glossary dd,.system-proof figcaption{overflow-wrap:anywhere}

@media(max-width:1280px){
  :root{--rail:310px}.cover{grid-template-columns:1fr;gap:42px}.cover-visual{max-width:900px}.system-proof figcaption{grid-template-columns:1fr}.system-proof figcaption small{text-align:left}
}

@media(max-width:860px){
  :root{--top:68px}.top-actions [data-fast-toggle]{display:none}.top-actions [data-theme-toggle]{display:flex}.mobile-picker{background:var(--rail-bg)}
  .mobile-picker label{font-size:.8125rem;line-height:1.35}.mobile-picker select{min-height:48px;height:auto;font-size:1rem}
}

@media(max-width:640px){
  body{font-size:1.125rem}.book-id strong{font-size:.875rem}.top-actions{gap:6px}.top-actions [data-theme-toggle],.top-actions a{width:44px;min-width:44px;padding:0}.theme-toggle span{display:none}
  .cover,.scope,.deep-questions,.chapter,footer{padding-left:18px;padding-right:18px}.cover h1{font-size:clamp(2.625rem,15vw,3.9375rem);overflow-wrap:anywhere}
  .cover-subtitle{font-size:.9375rem}.cover-lede{font-size:1.125rem}.chapter-head h2{font-size:clamp(2.25rem,11vw,3rem);overflow-wrap:anywhere}.chapter-subtitle{font-size:1.125rem}
  .teaching-visual,.system-proof{margin-left:-18px;margin-right:-18px}
  .thirty p{font-size:1.4375rem}.knowledge-check summary{font-size:1.25rem}.source-card{min-height:0}.mechanic{min-height:0}
}

@media(max-width:420px){
  .mobile-picker{grid-template-columns:1fr;gap:5px}.book-id strong{max-width:28vw;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
}

@media(max-width:340px){
  .book-id span{display:none}.book-id{margin-left:6px}.cover,.scope,.deep-questions,.chapter,footer{padding-left:12px;padding-right:12px}.teaching-visual,.system-proof{margin-left:-12px;margin-right:-12px}
}

@media print{
  :root,:root[data-theme]{color-scheme:light;--bg:#fff;--panel:#fff;--panel-2:#fff;--panel-3:#fff;--text:#14232b;--text-body:#293941;--muted:#53636b;--muted-2:#5f6e75;--line:#cbd2d1;--line-2:#aeb9b8;--brass:#765819;--brass-soft:#5d470f;--mint:#176a58;--cyan:#17677a;--red:#a23f3b;--knowledge-bg:#fff;--knowledge-border:#a18a4b;--knowledge-text:#42391f;--shadow:none}
  body{background:#fff;font-size:12pt}.topbar,.progress,.rail,.mobile-picker,.theme-toggle,.cover-actions,.chapter-search,.glossary-search{display:none!important}.cover-visual>img,.teaching-visual img,.system-proof{box-shadow:none}
}