:root {
  --ink: #edf2f2;
  --muted: #97a9ad;
  --dim: #60747a;
  --bg: #0d141d;
  --panel: #141f2b;
  --panel-2: #182735;
  --line: rgba(206, 230, 229, .13);
  --cyan: #76e0d1;
  --cyan-dark: #164a4c;
  --amber: #ffc56d;
  --amber-dark: #503719;
  --rose: #fb8f89;
  --green: #9de5a7;
  --shadow: 0 18px 50px rgba(0,0,0,.24);
  --serif: Georgia, 'Songti SC', 'Noto Serif SC', serif;
  --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft Yahei', sans-serif;
  --mono: 'SFMono-Regular', Consolas, 'Liberation Mono', monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: radial-gradient(circle at 84% -10%, #244656 0, transparent 32rem), var(--bg); font-family: var(--sans); line-height: 1.65; }
button, input { font: inherit; }
button { color: inherit; }
a { color: inherit; }

.app-shell { min-height: 100vh; }
.topbar { height: 76px; border-bottom: 1px solid var(--line); background: rgba(13,20,29,.88); backdrop-filter: blur(18px); position: sticky; top: 0; z-index: 20; display: flex; justify-content: space-between; align-items: center; padding: 0 32px; }
.brand-lockup, .topbar-actions, .brand { display: flex; align-items: center; }
.brand { gap: 12px; text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 38px; height: 38px; border: 1px solid var(--cyan); color: var(--cyan); font: 700 13px var(--mono); letter-spacing: -.08em; transform: rotate(-4deg); }
.brand strong, .brand small { display: block; }
.brand strong { font: 600 16px var(--serif); letter-spacing: .03em; }
.brand small { color: var(--muted); font-size: 11px; margin-top: 1px; }
.topbar-actions { gap: 14px; }
.search-wrap { width: min(310px, 34vw); display: flex; align-items: center; gap: 8px; border: 1px solid var(--line); background: rgba(255,255,255,.035); padding: 7px 11px; color: var(--dim); }
.search-wrap input { min-width: 0; width: 100%; border: 0; outline: 0; background: transparent; color: var(--ink); font-size: 13px; }
.search-wrap input::placeholder { color: var(--dim); }
.ghost-btn, .link-btn { border: 1px solid var(--line); background: transparent; color: var(--muted); padding: 8px 12px; cursor: pointer; transition: .2s ease; }
.ghost-btn:hover, .link-btn:hover { border-color: var(--cyan); color: var(--cyan); }
.mobile-menu { display: none; border: 0; background: transparent; font-size: 21px; margin-right: 8px; cursor: pointer; }

.layout { display: grid; grid-template-columns: 286px minmax(0,1fr); min-height: calc(100vh - 76px); }
.sidebar { border-right: 1px solid var(--line); padding: 31px 19px 24px; display: flex; flex-direction: column; position: sticky; top: 76px; height: calc(100vh - 76px); overflow-y: auto; background: rgba(9,15,23,.45); }
.sidebar-intro { padding: 0 12px 22px; border-bottom: 1px solid var(--line); }
.eyebrow, .nav-label, .micro-label { color: var(--cyan); font: 700 10px var(--mono); text-transform: uppercase; letter-spacing: .16em; }
.sidebar-intro p { color: var(--muted); font-size: 12px; line-height: 1.65; margin: 11px 0 0; }
.nav-list { padding-top: 18px; }
.nav-label { color: var(--dim); margin: 21px 12px 7px; }
.nav-item { width: 100%; display: grid; grid-template-columns: 27px 1fr auto; align-items: center; text-align: left; gap: 9px; border: 1px solid transparent; background: transparent; color: var(--muted); padding: 10px 11px; margin: 2px 0; cursor: pointer; font-size: 13px; transition: .18s ease; }
.nav-item:hover { color: var(--ink); background: rgba(255,255,255,.035); }
.nav-item.active { color: var(--ink); border-color: rgba(118,224,209,.25); background: linear-gradient(90deg, rgba(118,224,209,.12), rgba(118,224,209,.025)); }
.nav-item b { color: var(--dim); font: 11px var(--mono); font-weight: 400; }
.nav-item.active b { color: var(--cyan); }
.nav-no { font: 11px var(--mono); color: var(--cyan); }
.sidebar-foot { margin-top: auto; border-top: 1px solid var(--line); padding: 18px 12px 0; }
.progress-mini { display: flex; justify-content: space-between; color: var(--muted); font-size: 11px; }
.progress-mini strong { color: var(--cyan); font: 12px var(--mono); }
.progress-track { height: 4px; background: #22313c; margin: 9px 0 12px; overflow: hidden; }
.progress-track i { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--cyan), var(--amber)); transition: width .3s ease; }
.sidebar-foot p { color: var(--dim); font-size: 10px; line-height: 1.6; margin: 0; }

.main { max-width: 1230px; width: 100%; padding: 44px clamp(22px, 4vw, 64px) 80px; margin: 0 auto; outline: 0; }
.view { animation: enter .28s ease both; }
@keyframes enter { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }
.hero { display: grid; grid-template-columns: minmax(0,1.25fr) minmax(290px,.75fr); gap: 34px; align-items: end; padding-bottom: 35px; border-bottom: 1px solid var(--line); }
.hero-kicker { color: var(--amber); font: 700 11px var(--mono); letter-spacing: .15em; text-transform: uppercase; }
.hero h1 { font: 500 clamp(40px, 6vw, 78px)/.98 var(--serif); letter-spacing: -.055em; margin: 13px 0 22px; max-width: 710px; }
.hero h1 em { color: var(--cyan); font-style: normal; }
.hero-lead { color: var(--muted); font-size: 15px; max-width: 650px; margin: 0; }
.hero-note { color: var(--dim); font-size: 11px; border-left: 2px solid var(--amber); padding-left: 13px; margin: 19px 0 0; }
.priority-board { border: 1px solid var(--line); background: linear-gradient(145deg, rgba(255,255,255,.055), rgba(255,255,255,.012)); padding: 18px; box-shadow: var(--shadow); }
.priority-board h3 { font: 500 20px var(--serif); margin: 0 0 15px; }
.priority-row { display: grid; grid-template-columns: 35px 1fr 30px; align-items: center; gap: 9px; margin: 12px 0; font-size: 12px; }
.priority-row .index { color: var(--amber); font: 11px var(--mono); }
.priority-bar { height: 6px; background: #26343e; position: relative; }
.priority-bar i { display: block; height: 100%; background: var(--cyan); }
.priority-row strong { color: var(--ink); font: 12px var(--mono); text-align: right; }

.section-head { display: flex; justify-content: space-between; align-items: end; gap: 20px; margin: 42px 0 17px; }
.section-head h2 { font: 500 clamp(25px, 3vw, 36px)/1.1 var(--serif); letter-spacing: -.035em; margin: 0; }
.section-head p { color: var(--muted); font-size: 12px; max-width: 470px; margin: 0; }
.section-head .eyebrow { color: var(--amber); margin-bottom: 7px; }
.facts-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 10px; }
.fact-card { border: 1px solid var(--line); background: rgba(255,255,255,.025); padding: 16px; min-height: 108px; }
.fact-card .fact-label { color: var(--dim); font-size: 11px; }
.fact-card strong { display: block; color: var(--ink); font: 500 19px/1.18 var(--serif); margin: 7px 0 8px; }
.fact-card small { color: var(--muted); font-size: 10px; line-height: 1.5; }
.fact-card.is-check { border-color: rgba(255,197,109,.3); }
.fact-card.is-check strong { color: var(--amber); font-size: 16px; }

.chapter-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 12px; }
.chapter-card { border: 1px solid var(--line); background: linear-gradient(150deg, rgba(255,255,255,.045), rgba(255,255,255,.01)); padding: 19px; min-height: 200px; display: flex; flex-direction: column; position: relative; overflow: hidden; cursor: pointer; transition: .2s ease; }
.chapter-card:hover { border-color: rgba(118,224,209,.55); transform: translateY(-2px); box-shadow: var(--shadow); }
.chapter-card.priority-high { border-top: 2px solid var(--amber); }
.chapter-card.priority-mid { border-top: 2px solid var(--cyan); }
.chapter-card .chapter-num { color: var(--cyan); font: 12px var(--mono); }
.chapter-card h3 { font: 500 24px var(--serif); margin: 13px 0 5px; }
.chapter-card p { color: var(--muted); font-size: 12px; line-height: 1.6; margin: 0; }
.chapter-card .card-foot { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: auto; padding-top: 18px; color: var(--dim); font-size: 10px; }
.tag { display: inline-flex; align-items: center; border: 1px solid var(--line); color: var(--muted); padding: 3px 7px; font: 10px var(--mono); }
.tag.high { color: var(--amber); border-color: rgba(255,197,109,.35); }
.tag.cyan { color: var(--cyan); border-color: rgba(118,224,209,.35); }
.arrow { color: var(--cyan); font-size: 18px; }

.map-strip { display: flex; flex-wrap: wrap; align-items: stretch; gap: 0; border: 1px solid var(--line); background: rgba(255,255,255,.022); margin-top: 13px; }
.map-node { flex: 1 1 120px; min-height: 73px; display: flex; flex-direction: column; justify-content: center; padding: 12px 15px; border-right: 1px solid var(--line); position: relative; }
.map-node:last-child { border-right: 0; }
.map-node:not(:last-child)::after { content: '→'; position: absolute; right: -8px; top: 25px; color: var(--amber); background: var(--bg); padding: 0 2px; z-index: 1; }
.map-node strong { font: 500 14px var(--serif); }
.map-node small { color: var(--dim); font-size: 10px; margin-top: 3px; }

.callout { border-left: 2px solid var(--cyan); background: rgba(118,224,209,.065); padding: 14px 16px; color: var(--muted); font-size: 13px; margin: 20px 0; }
.callout strong { color: var(--cyan); }
.evidence-chip { display: inline-flex; color: var(--cyan); border: 1px solid rgba(118,224,209,.25); padding: 3px 7px; font: 10px var(--mono); margin-right: 5px; }
.source-line { color: var(--dim); font: 10px/1.5 var(--mono); margin-top: 9px; }
.source-line a { color: var(--cyan); text-decoration: none; }
.source-line a:hover { text-decoration: underline; }

.chapter-header { border-bottom: 1px solid var(--line); padding-bottom: 25px; }
.chapter-header .back-link { color: var(--cyan); background: none; border: 0; padding: 0; cursor: pointer; font: 11px var(--mono); }
.chapter-title-row { display: flex; justify-content: space-between; align-items: end; gap: 18px; margin-top: 18px; }
.chapter-title-row h1 { font: 500 clamp(37px, 5vw, 61px)/1 var(--serif); letter-spacing: -.05em; margin: 0; }
.chapter-title-row h1 span { display: block; color: var(--cyan); font: 12px var(--mono); letter-spacing: .13em; margin-bottom: 11px; }
.chapter-title-row p { max-width: 480px; color: var(--muted); font-size: 13px; margin: 0; }
.chapter-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 17px; }
.chapter-body { display: grid; grid-template-columns: minmax(0,1.25fr) minmax(250px,.75fr); gap: 30px; margin-top: 28px; }
.section-card { border-top: 1px solid var(--line); padding: 18px 0 19px; }
.section-card h3 { font: 500 22px var(--serif); margin: 0 0 7px; }
.section-card p { color: var(--muted); font-size: 13px; margin: 0; }
.section-card .trap { margin-top: 12px; border-left: 2px solid var(--amber); padding-left: 11px; color: #e9c98f; font-size: 12px; }
.section-card .trap b { font: 10px var(--mono); color: var(--amber); margin-right: 7px; }
.worked-card { border: 1px solid rgba(255,197,109,.25); background: linear-gradient(145deg, rgba(255,197,109,.08), rgba(255,255,255,.015)); padding: 18px; margin-top: 10px; }
.worked-card h3 { font: 500 20px var(--serif); margin: 0 0 10px; }
.worked-card p { color: var(--muted); font-size: 12px; margin: 0; }
.step-list { counter-reset: step; list-style: none; margin: 14px 0 0; padding: 0; }
.step-list li { counter-increment: step; display: grid; grid-template-columns: 25px 1fr; gap: 8px; color: var(--muted); font-size: 12px; margin: 8px 0; }
.step-list li::before { content: counter(step, decimal-leading-zero); color: var(--amber); font: 10px var(--mono); padding-top: 3px; }
.sidebar-stack { position: sticky; top: 103px; align-self: start; }
.mini-panel { border: 1px solid var(--line); background: rgba(255,255,255,.03); padding: 17px; margin-bottom: 13px; }
.mini-panel h3 { font: 500 19px var(--serif); margin: 0 0 11px; }
.mini-panel p { color: var(--muted); font-size: 12px; margin: 0; }
.graph-list { display: flex; flex-direction: column; gap: 0; margin-top: 12px; }
.graph-list span { display: flex; align-items: center; gap: 9px; color: var(--muted); font-size: 11px; padding: 8px 0; border-bottom: 1px solid var(--line); }
.graph-list span::before { content: '↳'; color: var(--cyan); font: 13px var(--mono); }

.questions-toolbar { display: flex; flex-wrap: wrap; gap: 8px; border: 1px solid var(--line); padding: 12px; background: rgba(255,255,255,.025); }
.filter-btn { cursor: pointer; border: 1px solid var(--line); background: transparent; color: var(--muted); padding: 7px 10px; font-size: 11px; }
.filter-btn.active, .filter-btn:hover { border-color: var(--cyan); color: var(--cyan); background: rgba(118,224,209,.06); }
.question-list { display: grid; gap: 11px; margin-top: 15px; }
.question-card { border: 1px solid var(--line); background: rgba(255,255,255,.025); padding: 18px; }
.question-card.is-wrong { border-color: rgba(251,143,137,.55); }
.question-top { display: flex; justify-content: space-between; gap: 12px; align-items: start; }
.question-top h3 { font: 500 19px/1.3 var(--serif); margin: 7px 0 0; }
.question-num { color: var(--cyan); font: 10px var(--mono); }
.question-prompt { color: var(--muted); font-size: 13px; margin: 13px 0 0; white-space: pre-line; }
.question-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 15px; }
.action-btn { cursor: pointer; border: 1px solid var(--line); background: transparent; color: var(--muted); padding: 7px 10px; font-size: 11px; }
.action-btn:hover { color: var(--ink); border-color: var(--cyan); }
.action-btn.answer { color: var(--cyan); border-color: rgba(118,224,209,.4); }
.action-btn.wrong { color: var(--rose); border-color: rgba(251,143,137,.38); }
.answer-panel { border-top: 1px solid var(--line); margin-top: 15px; padding-top: 15px; }
.answer-panel p { color: var(--ink); font-size: 13px; margin: 0; }
.answer-panel h4 { color: var(--amber); font: 10px var(--mono); letter-spacing: .12em; text-transform: uppercase; margin: 15px 0 7px; }
.answer-panel .source-line { margin-top: 14px; }
.empty-state { border: 1px dashed var(--line); color: var(--muted); padding: 32px 22px; text-align: center; }

.mock-shell { border: 1px solid var(--line); background: linear-gradient(145deg, rgba(118,224,209,.08), rgba(255,255,255,.015)); padding: clamp(20px, 4vw, 38px); }
.mock-top { display: flex; justify-content: space-between; gap: 18px; align-items: start; border-bottom: 1px solid var(--line); padding-bottom: 18px; }
.mock-top h1 { font: 500 clamp(34px, 5vw, 58px)/1 var(--serif); letter-spacing: -.05em; margin: 0; }
.mock-top p { color: var(--muted); font-size: 12px; max-width: 390px; margin: 4px 0 0; }
.score-box { text-align: right; min-width: 96px; }
.score-box strong { display: block; color: var(--cyan); font: 500 36px var(--mono); }
.score-box span { color: var(--dim); font-size: 10px; }
.mock-question { padding: 25px 0 0; }
.mock-question h2 { font: 500 25px/1.28 var(--serif); margin: 7px 0 12px; }
.mock-question .prompt { color: var(--muted); font-size: 14px; white-space: pre-line; }
.mock-options { display: grid; gap: 8px; margin-top: 18px; }
.mock-option { cursor: pointer; border: 1px solid var(--line); background: rgba(0,0,0,.13); color: var(--muted); text-align: left; padding: 11px 13px; font-size: 12px; }
.mock-option:hover, .mock-option.selected { border-color: var(--cyan); color: var(--ink); }
.mock-result { border-top: 1px solid var(--line); margin-top: 22px; padding-top: 17px; color: var(--muted); font-size: 13px; }
.mock-result strong { color: var(--cyan); }
.mock-controls { display: flex; justify-content: space-between; gap: 10px; margin-top: 25px; }
.primary-btn { cursor: pointer; border: 1px solid var(--cyan); background: var(--cyan); color: #102023; padding: 10px 15px; font-weight: 700; font-size: 12px; }
.primary-btn:hover { filter: brightness(1.08); }
.primary-btn:disabled { opacity: .4; cursor: not-allowed; }

.source-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 12px; }
.source-card { border: 1px solid var(--line); padding: 18px; background: rgba(255,255,255,.025); }
.source-card h3 { font: 500 21px var(--serif); margin: 0 0 8px; }
.source-card p { color: var(--muted); font-size: 12px; margin: 0 0 13px; }
.source-card a { color: var(--cyan); font: 11px var(--mono); text-decoration: none; word-break: break-all; }
.source-card a:hover { text-decoration: underline; }
.provenance-table { width: 100%; border-collapse: collapse; font-size: 11px; margin-top: 17px; }
.provenance-table th, .provenance-table td { border-bottom: 1px solid var(--line); padding: 10px 8px; text-align: left; vertical-align: top; }
.provenance-table th { color: var(--dim); font: 10px var(--mono); text-transform: uppercase; }
.provenance-table td { color: var(--muted); }
.provenance-table td:first-child { color: var(--ink); }

.toast { position: fixed; right: 26px; bottom: 24px; z-index: 30; pointer-events: none; transform: translateY(12px); opacity: 0; background: #203a3d; border: 1px solid rgba(118,224,209,.35); color: var(--ink); padding: 10px 14px; font-size: 12px; transition: .25s ease; }
.toast.show { transform: translateY(0); opacity: 1; }

/* Beginner route: one page, one action, one next step. */
.path-progress-row { display: flex; justify-content: space-between; align-items: end; gap: 20px; border-bottom: 1px solid var(--line); padding-bottom: 18px; }
.path-progress-row h1 { font: 500 clamp(28px, 4vw, 48px)/1.05 var(--serif); letter-spacing: -.045em; margin: 9px 0 0; }
.path-progress-number { text-align: right; min-width: 90px; }
.path-progress-number strong { display: block; color: var(--cyan); font: 500 30px var(--mono); }
.path-progress-number span { color: var(--dim); font-size: 10px; }
.path-rail { height: 5px; background: #22313c; margin: 18px 0 15px; overflow: hidden; }
.path-rail i { display: block; height: 100%; background: linear-gradient(90deg, var(--cyan), var(--amber)); transition: width .3s ease; }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 18px; }
.lesson-card { max-width: 880px; border: 1px solid rgba(118,224,209,.25); background: linear-gradient(145deg, rgba(118,224,209,.07), rgba(255,255,255,.018)); padding: clamp(20px, 4vw, 42px); box-shadow: var(--shadow); }
.lesson-kicker, .section-label { color: var(--amber); font: 700 10px var(--mono); letter-spacing: .16em; text-transform: uppercase; }
.lesson-card h2 { font: 500 clamp(30px, 5vw, 53px)/1.06 var(--serif); letter-spacing: -.045em; margin: 11px 0 8px; max-width: 720px; }
.lesson-goal { color: var(--ink); font-size: 16px; max-width: 670px; margin: 0 0 25px; }
.why-box, .example-box, .micro-practice, .reveal-box { border-top: 1px solid var(--line); padding: 21px 0; }
.why-box { border-left: 2px solid var(--amber); padding-left: 15px; background: rgba(255,197,109,.035); padding-right: 13px; }
.why-box strong { color: var(--amber); font-size: 12px; }
.why-box p, .lesson-section p, .example-box p { color: var(--muted); font-size: 14px; margin: 7px 0 0; max-width: 740px; }
.example-box { border-bottom: 1px solid var(--line); background: rgba(0,0,0,.08); padding: 20px 17px; }
.example-box .section-label { color: var(--cyan); }
.micro-practice { margin-top: 7px; }
.micro-practice h3 { font: 500 21px/1.35 var(--serif); margin: 8px 0 13px; max-width: 730px; }
.practice-options { display: grid; gap: 8px; max-width: 760px; }
.practice-option { cursor: pointer; border: 1px solid var(--line); background: rgba(0,0,0,.14); color: var(--muted); text-align: left; padding: 11px 13px; font-size: 13px; transition: .18s ease; }
.practice-option:hover { color: var(--ink); border-color: var(--cyan); transform: translateX(2px); }
.practice-option.selected.correct { border-color: var(--green); color: var(--green); background: rgba(157,229,167,.08); }
.practice-option.selected.wrong { border-color: var(--rose); color: var(--rose); background: rgba(251,143,137,.07); }
.practice-feedback { margin-top: 14px; border-left: 2px solid var(--cyan); padding: 10px 13px; background: rgba(118,224,209,.06); }
.micro-practice.is-wrong .practice-feedback { border-color: var(--rose); background: rgba(251,143,137,.06); }
.practice-feedback strong { color: var(--cyan); font-size: 12px; }
.micro-practice.is-wrong .practice-feedback strong { color: var(--rose); }
.practice-feedback p { color: var(--muted); font-size: 13px; margin: 4px 0 0; }
.practice-hint, .reveal-intro { color: var(--dim); font-size: 11px; margin: 11px 0 0; }
.reveal-box { border-top: 1px solid rgba(255,197,109,.3); background: rgba(255,197,109,.035); padding: 20px 17px; }
.reveal-intro { margin-top: 7px; }
.reveal-step { display: grid; grid-template-columns: 28px 1fr; gap: 10px; border-top: 1px solid var(--line); padding: 15px 0; }
.reveal-step > span { display: grid; place-items: center; width: 25px; height: 25px; color: #122024; background: var(--amber); font: 11px var(--mono); }
.reveal-step strong { font-size: 13px; color: var(--ink); }
.reveal-step p { color: var(--muted); font-size: 13px; margin: 3px 0 0; }
.reveal-complete { border-top: 1px solid var(--line); padding-top: 13px; color: var(--green); font-size: 12px; }
.lesson-next { display: flex; justify-content: space-between; align-items: end; gap: 15px; border-top: 1px solid var(--line); padding-top: 20px; margin-top: 10px; }
.lesson-next strong { display: block; color: var(--ink); font: 500 19px var(--serif); margin-top: 5px; }
.lesson-next p { color: var(--muted); font-size: 11px; max-width: 520px; margin: 4px 0 0; }
.lesson-footer { max-width: 880px; display: flex; justify-content: space-between; align-items: center; gap: 12px; color: var(--dim); font-size: 10px; padding-top: 15px; }
.back-link, .inline-link, .text-btn { border: 0; background: transparent; color: var(--cyan); cursor: pointer; padding: 0; font: inherit; }
.back-link:disabled { color: var(--dim); cursor: not-allowed; }
.secondary-btn { cursor: pointer; border: 1px solid var(--line); background: transparent; color: var(--muted); padding: 8px 11px; font-size: 11px; }
.secondary-btn:hover, .text-btn:hover { border-color: var(--cyan); color: var(--cyan); }
.section-head.compact { margin-top: 32px; }
.review-grid, .lookup-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.review-card, .lookup-card { border: 1px solid var(--line); background: rgba(255,255,255,.025); padding: 18px; }
.review-card-top, .lookup-card-top { display: flex; justify-content: space-between; align-items: center; }
.review-card h3, .lookup-card h3 { font: 500 22px var(--serif); margin: 12px 0 5px; }
.review-card p, .lookup-card > p { color: var(--muted); font-size: 12px; margin: 0; }
.review-track { height: 4px; background: #26343e; margin: 16px 0 13px; }
.review-track i { display: block; height: 100%; background: var(--cyan); }
.recovery-links { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.recovery-link { cursor: pointer; border: 1px solid var(--line); text-align: left; background: rgba(255,255,255,.025); padding: 14px; }
.recovery-link:hover { border-color: var(--cyan); transform: translateY(-1px); }
.recovery-link span { display: block; color: var(--rose); font: 10px var(--mono); text-transform: uppercase; }
.recovery-link strong { display: block; color: var(--ink); font: 500 17px var(--serif); margin: 5px 0; }
.recovery-link small { color: var(--dim); font-size: 10px; }
.lookup-card { overflow: hidden; }
.lookup-card-top .chapter-num { color: var(--cyan); font: 12px var(--mono); }
.lookup-actions { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin: 14px 0 3px; color: var(--dim); font-size: 10px; }
.lookup-sections details { border-top: 1px solid var(--line); padding: 10px 0; }
.lookup-sections summary { cursor: pointer; color: var(--ink); font-size: 12px; }
.lookup-sections summary span { float: right; color: var(--amber); font: 10px var(--mono); }
.lookup-sections details p { color: var(--muted); font-size: 12px; margin: 8px 0 0; }
.trap-note { border-left: 2px solid var(--amber); color: #e9c98f; font-size: 11px; margin-top: 9px; padding-left: 9px; }
.trap-note strong { color: var(--amber); }
.lookup-worked { border-top: 1px solid rgba(255,197,109,.25); background: rgba(255,197,109,.035); margin-top: 12px; padding: 13px; }
.lookup-worked strong { font: 500 15px var(--serif); }
.lookup-worked ol { color: var(--muted); font-size: 11px; margin: 8px 0 0 18px; padding: 0; }
.lookup-worked li { margin: 4px 0; }

@media (max-width: 930px) {
  .topbar { padding: 0 19px; }
  .ghost-btn { display: none; }
  .layout { grid-template-columns: 1fr; }
  .sidebar { position: fixed; z-index: 15; left: 0; top: 76px; width: 286px; height: calc(100vh - 76px); transform: translateX(-101%); transition: transform .25s ease; box-shadow: 20px 0 50px rgba(0,0,0,.32); }
  .sidebar.open { transform: translateX(0); }
  .mobile-menu { display: block; }
  .main { padding-top: 31px; }
  .hero, .chapter-body { grid-template-columns: 1fr; }
  .sidebar-stack { position: static; }
}
@media (max-width: 680px) {
  .topbar { height: 68px; }
  .sidebar { top: 68px; height: calc(100vh - 68px); }
  .brand small { display: none; }
  .brand strong { font-size: 14px; }
  .search-wrap { width: 40px; padding: 8px; }
  .search-wrap span { font-size: 18px; }
  .search-wrap input { display: none; }
  .main { padding: 27px 17px 55px; }
  .hero { gap: 22px; padding-bottom: 27px; }
  .hero h1 { font-size: 46px; }
  .hero-lead { font-size: 13px; }
  .facts-grid, .chapter-grid, .source-grid { grid-template-columns: 1fr; }
  .section-head { display: block; margin-top: 30px; }
  .section-head p { margin-top: 8px; }
  .map-strip { display: grid; grid-template-columns: 1fr 1fr; }
  .map-node { border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
  .map-node:nth-child(2n) { border-right: 0; }
  .map-node:nth-last-child(-n+2) { border-bottom: 0; }
  .map-node:not(:last-child)::after { display: none; }
  .chapter-title-row { display: block; }
  .chapter-title-row p { margin-top: 15px; }
  .chapter-title-row h1 { font-size: 43px; }
  .mock-top { display: block; }
  .score-box { text-align: left; margin-top: 12px; }
  .mock-controls { display: grid; grid-template-columns: 1fr 1fr; }
  .provenance-table { display: block; overflow-x: auto; white-space: nowrap; }
  .toast { right: 17px; bottom: 17px; left: 17px; text-align: center; }
  .path-progress-row { align-items: start; }
  .path-progress-row h1 { font-size: 29px; }
  .path-progress-number strong { font-size: 23px; }
  .lesson-card { padding: 21px 17px; }
  .lesson-card h2 { font-size: 34px; }
  .lesson-goal { font-size: 14px; }
  .why-box p, .lesson-section p, .example-box p { font-size: 13px; }
  .lesson-next { display: block; }
  .lesson-next .primary-btn { margin-top: 13px; width: 100%; }
  .lesson-footer { display: grid; grid-template-columns: 1fr 1fr; align-items: start; }
  .lesson-footer span { grid-column: 1 / -1; grid-row: 1; }
  .review-grid, .lookup-grid, .recovery-links { grid-template-columns: 1fr; }
  .lookup-actions { display: block; }
  .lookup-actions span { display: block; margin-top: 9px; }
}