:root {
  --ink: #07121d;
  --ink-2: #0c1b29;
  --panel: #102435;
  --paper: #f4f1e9;
  --paper-2: #e9e5da;
  --muted: #91a2af;
  --accent: #ffb11b;
  --accent-2: #e18b00;
  --blue: #3bb9ff;
  --green: #63d5a1;
  --red: #ff796f;
  --line: rgba(255, 255, 255, 0.13);
  --paper-line: rgba(7, 18, 29, 0.15);
  --sidebar: 270px;
  --radius: 14px;
  font-family: "Manrope", system-ui, sans-serif;
  color: var(--paper);
  background: var(--ink);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--ink); }
button, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; }
.skip-link { position: fixed; left: 1rem; top: -4rem; z-index: 100; padding: .75rem 1rem; background: var(--accent); color: var(--ink); font-weight: 800; }
.skip-link:focus { top: 1rem; }

.app-shell { min-height: 100vh; }
.sidebar { position: fixed; inset: 0 auto 0 0; z-index: 10; width: var(--sidebar); padding: 32px 26px; border-right: 1px solid var(--line); background: #081521; display: flex; flex-direction: column; }
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; }
.brand-mark { width: 48px; height: 48px; display: grid; place-items: center; background: var(--accent); color: var(--ink); font: 500 13px "IBM Plex Mono", monospace; border-radius: 2px 14px 2px 2px; }
.brand strong { display: block; font-size: 22px; letter-spacing: -.04em; }
.brand small { display: block; margin-top: 1px; color: var(--muted); font: 500 9px "IBM Plex Mono", monospace; letter-spacing: .08em; }
.main-nav { display: grid; gap: 7px; margin-top: 54px; }
.main-nav a { padding: 12px 13px; color: #b9c5cc; border-radius: 8px; text-decoration: none; font-size: 14px; font-weight: 600; }
.main-nav a span { margin-right: 14px; color: #607483; font: 12px "IBM Plex Mono", monospace; }
.main-nav a:hover, .main-nav a.active { color: white; background: rgba(255,255,255,.06); }
.main-nav a.active span { color: var(--accent); }
.sidebar-progress { margin-top: auto; padding: 17px; border: 1px solid var(--line); border-radius: 12px; background: rgba(255,255,255,.025); }
.sidebar-progress .label-row { display: flex; justify-content: space-between; font-size: 12px; color: var(--muted); }
.progress-track { height: 6px; margin-top: 10px; overflow: hidden; background: #223646; border-radius: 99px; }
.progress-fill { height: 100%; background: var(--accent); border-radius: inherit; transition: width .35s ease; }
.sidebar-note { margin: 20px 4px 0; color: #5f7484; font: 11px/1.6 "IBM Plex Mono", monospace; }
.mobile-header, .mobile-nav { display: none; }

main { margin-left: var(--sidebar); min-height: 100vh; }
.page { max-width: 1260px; margin: 0 auto; padding: 52px 56px 80px; animation: enter .25s ease; }
@keyframes enter { from { opacity: 0; transform: translateY(5px); } }
.eyebrow { margin: 0 0 12px; color: var(--accent); font: 500 12px "IBM Plex Mono", monospace; letter-spacing: .08em; text-transform: uppercase; }
h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 920px; margin-bottom: 18px; font-size: clamp(38px, 5.2vw, 76px); line-height: .98; letter-spacing: -.065em; }
h2 { font-size: clamp(26px, 3vw, 40px); line-height: 1.08; letter-spacing: -.045em; }
h3 { font-size: 19px; letter-spacing: -.025em; }
.lead { max-width: 760px; color: #b8c5ce; font-size: clamp(17px, 2vw, 21px); line-height: 1.55; }
.mono { font-family: "IBM Plex Mono", monospace; }
.muted { color: var(--muted); }
.accent { color: var(--accent); }
.section { margin-top: 64px; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: 22px; }
.section-heading p { max-width: 560px; margin-bottom: 5px; color: var(--muted); }

.hero { position: relative; padding: 22px 0 26px; }
.hero::after { content: "SYSTEM / FLOW / TRUTH"; position: absolute; right: 0; top: 20px; writing-mode: vertical-rl; color: rgba(255,255,255,.08); font: 11px "IBM Plex Mono", monospace; letter-spacing: .18em; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 11px; margin-top: 31px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 0 19px; border: 1px solid var(--line); border-radius: 8px; background: transparent; color: white; text-decoration: none; cursor: pointer; font-weight: 700; transition: .18s ease; }
.button:hover { transform: translateY(-1px); border-color: rgba(255,255,255,.28); }
.button.primary { border-color: var(--accent); background: var(--accent); color: var(--ink); }
.button.subtle { min-height: 38px; padding: 0 13px; font-size: 13px; }
.button.done { border-color: rgba(99,213,161,.4); background: rgba(99,213,161,.1); color: var(--green); }

.stat-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; margin-top: 46px; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius); background: var(--line); }
.stat { padding: 23px; background: var(--ink-2); }
.stat strong { display: block; font-size: 28px; letter-spacing: -.05em; }
.stat span { color: var(--muted); font-size: 12px; }
.system-map { display: grid; grid-template-columns: repeat(7, 1fr); gap: 7px; }
.system-node { min-height: 116px; padding: 16px 13px; border: 1px solid var(--line); border-top: 3px solid var(--node); border-radius: 5px; background: var(--ink-2); }
.system-node span { display: block; color: var(--node); font: 11px "IBM Plex Mono", monospace; }
.system-node strong { display: block; margin-top: 19px; font-size: 13px; }

.next-card { display: grid; grid-template-columns: 1.2fr .8fr; overflow: hidden; border-radius: var(--radius); background: var(--accent); color: var(--ink); }
.next-card > div { padding: clamp(24px, 4vw, 46px); }
.next-card .next-meta { display: flex; flex-direction: column; justify-content: space-between; border-left: 1px solid rgba(7,18,29,.17); }
.next-card h2 { max-width: 680px; font-size: clamp(28px, 4vw, 52px); }
.next-card p { max-width: 650px; line-height: 1.55; }
.next-card .button { align-self: start; border-color: var(--ink); color: var(--ink); }

.module-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.module-card { position: relative; min-height: 260px; padding: 27px; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius); background: var(--ink-2); }
.module-card::after { content: attr(data-number); position: absolute; right: -5px; bottom: -28px; color: rgba(255,255,255,.035); font-size: 130px; font-weight: 800; letter-spacing: -.1em; }
.module-card .module-kicker { color: var(--accent); font: 11px "IBM Plex Mono", monospace; }
.module-card h3 { max-width: 380px; margin: 20px 0 11px; font-size: 25px; }
.module-card p { max-width: 450px; color: var(--muted); font-size: 14px; line-height: 1.55; }
.module-footer { position: absolute; inset: auto 27px 24px; z-index: 1; display: flex; align-items: center; justify-content: space-between; }
.module-footer a { color: white; font-size: 13px; text-decoration: none; font-weight: 700; }
.module-footer a:hover { color: var(--accent); }

.course-intro { display: grid; grid-template-columns: 1.4fr .6fr; gap: 30px; align-items: end; }
.course-metrics { padding: 22px; border: 1px solid var(--line); border-radius: var(--radius); }
.course-metrics strong { display: block; font-size: 33px; }
.course-metrics p { margin: 4px 0 18px; color: var(--muted); font-size: 12px; }
.course-metrics p:last-child { margin-bottom: 0; }
.module-list { display: grid; margin-top: 40px; border-top: 1px solid var(--line); }
.module-row { display: grid; grid-template-columns: 72px minmax(230px, .8fr) 1.4fr 110px; gap: 22px; align-items: center; min-height: 112px; border-bottom: 1px solid var(--line); }
.module-index { color: var(--accent); font: 13px "IBM Plex Mono", monospace; }
.module-row h2 { margin: 0; font-size: 23px; }
.module-row p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.5; }
.module-row a { text-align: right; text-decoration: none; font-size: 13px; font-weight: 700; }
.module-row a:hover { color: var(--accent); }

.lesson-layout { display: grid; grid-template-columns: minmax(0, 760px) 250px; gap: clamp(38px, 7vw, 92px); justify-content: center; }
.lesson-header { margin-bottom: 42px; padding-bottom: 31px; border-bottom: 1px solid var(--line); }
.lesson-header h1 { font-size: clamp(38px, 5vw, 64px); }
.lesson-header .meta { display: flex; gap: 20px; color: var(--muted); font: 12px "IBM Plex Mono", monospace; }
.lesson-block { margin: 46px 0; }
.lesson-block h2 { margin-bottom: 17px; font-size: 27px; }
.lesson-block p, .lesson-block li { color: #c5d0d6; font-size: 17px; line-height: 1.72; }
.lesson-block ul { padding-left: 22px; }
.insight { margin: 38px 0; padding: 24px 27px; border-left: 4px solid var(--accent); background: var(--panel); font-size: 20px; line-height: 1.55; }
.model-card { margin: 28px 0; padding: 23px; border: 1px solid var(--line); border-radius: 10px; background: #06101a; font: 14px/1.8 "IBM Plex Mono", monospace; color: #cfdae0; white-space: pre-line; }
.practice { padding: 28px; border-radius: var(--radius); background: var(--paper); color: var(--ink); }
.practice .eyebrow { color: var(--accent-2); }
.practice h2 { font-size: 28px; }
.practice ol { padding-left: 22px; }
.practice li { margin: 9px 0; line-height: 1.55; }
.criteria { display: grid; gap: 8px; margin: 20px 0; }
.criterion { display: flex; gap: 10px; align-items: flex-start; padding: 11px 13px; background: rgba(7,18,29,.06); border-radius: 7px; }
.criterion input { margin-top: 4px; accent-color: var(--ink); }
.notes { width: 100%; min-height: 145px; padding: 15px; border: 1px solid var(--paper-line); border-radius: 8px; background: white; color: var(--ink); resize: vertical; line-height: 1.5; }
.notes:focus { outline: 3px solid rgba(255,177,27,.35); border-color: var(--accent-2); }
.lesson-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }
.practice .button { border-color: var(--ink); color: var(--ink); }
.practice .button.primary { color: var(--ink); }
.lesson-aside { position: sticky; top: 35px; align-self: start; }
.lesson-aside .toc { display: grid; gap: 9px; padding: 18px; border: 1px solid var(--line); border-radius: 10px; }
.toc small { color: var(--muted); font: 10px "IBM Plex Mono", monospace; }
.toc a { color: #b6c3cc; font-size: 13px; text-decoration: none; }
.toc a:hover { color: var(--accent); }
.lesson-nav { display: grid; gap: 7px; margin-top: 13px; }

.diagnostic-grid { display: grid; grid-template-columns: minmax(0, 760px) 300px; gap: 50px; align-items: start; }
.question-card { margin: 14px 0; padding: 24px; border: 1px solid var(--line); border-radius: 11px; background: var(--ink-2); }
.question-card legend { padding: 0 8px; font-weight: 700; line-height: 1.5; }
.options { display: grid; gap: 8px; margin-top: 14px; }
.option { display: flex; gap: 10px; align-items: flex-start; padding: 12px; border: 1px solid var(--line); border-radius: 8px; color: #c3ced5; cursor: pointer; }
.option:has(input:checked) { border-color: var(--accent); background: rgba(255,177,27,.08); color: white; }
.option input { margin-top: 3px; accent-color: var(--accent); }
.diagnostic-result { position: sticky; top: 30px; padding: 24px; border-radius: var(--radius); background: var(--paper); color: var(--ink); }
.diagnostic-result h3 { font-size: 23px; }
.score-row { margin: 15px 0; }
.score-row div { display: flex; justify-content: space-between; font-size: 12px; }
.score-row .progress-track { background: #d6d1c7; }
.result-empty { color: #65717a; line-height: 1.5; }

.tool-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 36px; }
.tool-card { min-height: 250px; padding: 24px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--ink-2); display: flex; flex-direction: column; }
.tool-card .tool-number { color: var(--accent); font: 11px "IBM Plex Mono", monospace; }
.tool-card h3 { margin: 25px 0 10px; font-size: 21px; }
.tool-card p { color: var(--muted); font-size: 14px; line-height: 1.55; }
.tool-card button { margin-top: auto; align-self: flex-start; }
.principles { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.principle { padding: 22px; border-top: 2px solid var(--accent); background: var(--ink-2); }
.principle strong { display: block; margin-bottom: 8px; }
.principle p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.55; }
.toast { position: fixed; right: 24px; bottom: 24px; z-index: 50; padding: 12px 16px; border-radius: 8px; background: var(--paper); color: var(--ink); box-shadow: 0 16px 50px rgba(0,0,0,.35); font-size: 13px; font-weight: 700; opacity: 0; pointer-events: none; transform: translateY(12px); transition: .25s; }
.toast.show { opacity: 1; transform: translateY(0); }
.empty-state { padding: 60px 20px; text-align: center; }

@media (max-width: 1050px) {
  .system-map { grid-template-columns: repeat(4, 1fr); }
  .tool-grid { grid-template-columns: repeat(2, 1fr); }
  .lesson-layout { grid-template-columns: minmax(0, 720px); }
  .lesson-aside { position: static; order: -1; }
  .lesson-aside .toc { grid-template-columns: repeat(4, 1fr); }
}
@media (max-width: 820px) {
  .sidebar { display: none; }
  .mobile-header { position: sticky; top: 0; z-index: 20; height: 70px; padding: 11px 18px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); background: rgba(8,21,33,.96); backdrop-filter: blur(12px); }
  .mobile-header .brand-mark { width: 42px; height: 42px; }
  .menu-button { padding: 9px 12px; border: 1px solid var(--line); border-radius: 7px; background: transparent; color: white; }
  .mobile-nav { position: fixed; inset: 70px 0 auto; z-index: 19; padding: 12px 18px 18px; grid-template-columns: repeat(2, 1fr); gap: 7px; background: #081521; border-bottom: 1px solid var(--line); }
  .mobile-nav.open { display: grid; }
  .mobile-nav a { padding: 12px; border-radius: 7px; background: var(--ink-2); text-decoration: none; font-size: 14px; }
  main { margin-left: 0; }
  .page { padding: 38px 22px 64px; }
  .module-row { grid-template-columns: 50px 1fr 80px; padding: 20px 0; }
  .module-row p { grid-column: 2 / -1; grid-row: 2; }
  .diagnostic-grid { grid-template-columns: 1fr; }
  .diagnostic-result { position: static; }
}
@media (max-width: 620px) {
  .stat-grid { grid-template-columns: repeat(2, 1fr); }
  .system-map, .module-grid, .tool-grid, .principles { grid-template-columns: 1fr; }
  .next-card, .course-intro { grid-template-columns: 1fr; }
  .next-card .next-meta { border-top: 1px solid rgba(7,18,29,.17); border-left: 0; }
  .module-row { grid-template-columns: 40px 1fr; gap: 12px; }
  .module-row p { grid-column: 2; }
  .module-row a { grid-column: 2; text-align: left; }
  .lesson-aside .toc { grid-template-columns: repeat(2, 1fr); }
  .section-heading { align-items: start; flex-direction: column; }
  .hero::after { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; transition-duration: .01ms !important; }
}