:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --panel: #ffffff;
  --ink: #172033;
  --muted: #5d6b80;
  --line: #d9e0ea;
  --accent: #1f6feb;
  --accent-2: #0f766e;
  --danger: #b42318;
  --success: #1f8a4c;
  --shadow: 0 18px 50px rgba(28, 45, 74, 0.12);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-height: 100vh; background: var(--bg); color: var(--ink); font-family: "Segoe UI", Arial, sans-serif; }
a { color: var(--accent); }
.topbar { align-items: center; background: rgba(255,255,255,0.96); border-bottom: 1px solid var(--line); display: flex; gap: 24px; justify-content: space-between; min-height: 64px; padding: 0 28px; position: sticky; top: 0; z-index: 20; }
.brand { color: var(--ink); font-weight: 800; text-decoration: none; }
.topbar nav { display: flex; gap: 8px; }
.topbar nav a { border-radius: 6px; color: var(--muted); font-weight: 700; padding: 10px 12px; text-decoration: none; }
.topbar nav a:hover, .topbar nav a.active { background: #eaf1ff; color: var(--accent); }
.landing, .track-page { width: min(1180px, calc(100% - 32px)); margin: 0 auto; padding: 40px 0 56px; }
.landing-hero, .track-hero { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; box-shadow: var(--shadow); padding: 34px; }
.eyebrow { color: var(--accent); font-size: .82rem; font-weight: 800; letter-spacing: .04em; margin: 0 0 8px; text-transform: uppercase; }
h1 { font-size: 2.2rem; line-height: 1.12; margin: 0 0 12px; }
h2 { margin-top: 0; }
p { line-height: 1.58; }
.landing-hero p, .track-hero p { color: var(--muted); font-size: 1.05rem; max-width: 760px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 22px; }
.primary-action, .secondary-action, .resource-card a { border-radius: 6px; display: inline-flex; font-weight: 800; padding: 12px 15px; text-decoration: none; }
.primary-action { background: var(--accent); color: #fff; }
.secondary-action, .resource-card a { background: #e8eef8; color: var(--ink); }
.track-grid, .resource-grid { display: grid; gap: 16px; grid-template-columns: repeat(2, minmax(0, 1fr)); margin-top: 18px; }
.track-card, .resource-card { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 24px; }
.track-card span, .resource-card span { color: var(--muted); display: block; font-size: .82rem; font-weight: 800; letter-spacing: .04em; margin-bottom: 8px; text-transform: uppercase; }
.track-card p, .resource-card p { color: var(--muted); }
.metric-band { display: grid; gap: 12px; grid-template-columns: repeat(4, minmax(0, 1fr)); margin-top: 16px; }
.metric-band div { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 18px; }
.metric-band strong { display: block; font-size: 1.8rem; }
.metric-band span { color: var(--muted); }
.doc-layout { display: grid; grid-template-columns: 300px minmax(0, 1fr); gap: 24px; width: min(1280px, calc(100% - 32px)); margin: 0 auto; padding: 28px 0 56px; }
.doc-sidebar { align-self: start; background: var(--panel); border: 1px solid var(--line); border-radius: 8px; max-height: calc(100vh - 96px); overflow: auto; padding: 18px; position: sticky; top: 80px; }
.doc-sidebar h2 { font-size: 1rem; line-height: 1.35; margin: 12px 0; }
.back-link { font-weight: 800; text-decoration: none; }
.toc { display: grid; gap: 4px; }
.toc a { border-radius: 6px; color: var(--muted); font-size: .92rem; line-height: 1.3; padding: 7px 8px; text-decoration: none; }
.toc a:hover { background: #f0f5ff; color: var(--accent); }
.toc-level-3 { padding-left: 18px !important; }
.doc-content { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; box-shadow: var(--shadow); padding: 32px; }
.doc-content h1 { font-size: 2rem; }
.doc-content h2 { border-top: 1px solid var(--line); margin-top: 32px; padding-top: 26px; }
.doc-content h3 { margin-top: 24px; }
.doc-content li { line-height: 1.55; margin: 6px 0; }
.doc-content code { background: #edf2f9; border-radius: 4px; padding: 2px 5px; }
pre { background: #101828; border-radius: 8px; color: #f8fafc; overflow: auto; padding: 16px; }
.table-wrap { overflow-x: auto; }
table { border-collapse: collapse; margin: 16px 0; min-width: 680px; width: 100%; }
th, td { border: 1px solid var(--line); padding: 10px; text-align: left; vertical-align: top; }
th { background: #f3f6fb; }
@media (max-width: 860px) {
  .topbar { align-items: flex-start; flex-direction: column; gap: 8px; padding: 14px 16px; position: static; }
  .track-grid, .resource-grid, .metric-band, .doc-layout { grid-template-columns: 1fr; }
  .doc-sidebar { max-height: none; position: static; }
  .landing-hero, .track-hero, .doc-content { padding: 24px; }
}