:root {
    --navy: #080D1A;
    --slate: #0F1620;
    --card: #131C2B;
    --border: #1C2A3A;
    --border-bright: #243347;
    --cyan: #00C8F0;
    --cyan-dim: rgba(0,200,240,0.10);
    --green: #28E87A;
    --green-dim: rgba(40,232,122,0.10);
    --amber: #F0A800;
    --amber-dim: rgba(240,168,0,0.10);
    --red: #F04A6A;
    --red-dim: rgba(240,74,106,0.10);
    --purple: #9D6EFF;
    --purple-dim: rgba(157,110,255,0.10);
    --white: #E4EDF8;
    --muted: #7A8FA8;
    --sidebar-w: 270px;
  }

  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  html { scroll-behavior: smooth; }

  body {
    background: var(--navy);
    color: var(--white);
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    line-height: 1.7;
  }

  .topbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 200;
    height: 52px; display: flex; align-items: center; gap: 12px;
    padding: 0 20px;
    background: rgba(8,13,26,0.96);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
  }
  .topbar-logo { font-family: 'Space Grotesk', sans-serif; font-size: 17px; font-weight: 700; color: var(--white); text-decoration: none; }
  .topbar-logo span { color: var(--cyan); }
  .topbar-sep { color: var(--border-bright); }
  .topbar-title { font-family: 'JetBrains Mono', monospace; font-size: 12px; color: var(--muted); letter-spacing: 0.5px; }
  .topbar-right { margin-left: auto; display: flex; align-items: center; gap: 10px; }
  .score-pill { font-family: 'JetBrains Mono', monospace; font-size: 11px; color: var(--green); background: var(--green-dim); border: 1px solid rgba(40,232,122,0.25); padding: 3px 10px; border-radius: 20px; }
  .menu-btn { display: none; background: none; border: 1px solid var(--border); color: var(--white); padding: 5px 9px; border-radius: 5px; cursor: pointer; }

  .layout { display: flex; margin-top: 52px; }

  .sidebar {
    width: var(--sidebar-w); flex-shrink: 0;
    position: fixed; top: 52px; bottom: 0; left: 0;
    background: var(--slate); border-right: 1px solid var(--border);
    overflow-y: auto; padding: 16px 0;
    scrollbar-width: thin; scrollbar-color: var(--border) transparent;
  }
  .sidebar::-webkit-scrollbar { width: 3px; }
  .sidebar::-webkit-scrollbar-thumb { background: var(--border); }

  .sb-section-label { font-family: 'JetBrains Mono', monospace; font-size: 9px; letter-spacing: 1.8px; text-transform: uppercase; color: var(--muted); padding: 10px 16px 4px; }
  .sb-link { display: flex; align-items: center; gap: 9px; padding: 7px 16px; font-size: 12px; color: var(--muted); cursor: pointer; border-left: 2px solid transparent; transition: all 0.12s; text-decoration: none; }
  .sb-link:hover { color: var(--white); background: rgba(255,255,255,0.03); }
  .sb-link.active { color: var(--cyan); border-left-color: var(--cyan); background: var(--cyan-dim); }
  .sb-dot { width: 5px; height: 5px; border-radius: 50%; background: var(--border); flex-shrink: 0; }
  .sb-link.active .sb-dot { background: var(--cyan); box-shadow: 0 0 5px var(--cyan); }
  .sb-count { margin-left: auto; font-family: 'JetBrains Mono', monospace; font-size: 10px; color: var(--muted); background: rgba(255,255,255,0.05); padding: 1px 6px; border-radius: 3px; }

  .main { margin-left: var(--sidebar-w); flex: 1; max-width: 900px; padding: 40px 40px 120px; }

  .category { display: none; }
  .category.active { display: block; }

  .hero { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 40px; margin-bottom: 32px; position: relative; overflow: hidden; }
  .hero::after { content: ''; position: absolute; top: 0; right: 0; bottom: 0; width: 3px; background: linear-gradient(180deg, var(--cyan), var(--green), var(--purple)); }
  .hero-eyebrow { font-family: 'JetBrains Mono', monospace; font-size: 11px; color: var(--cyan); letter-spacing: 2px; text-transform: uppercase; margin-bottom: 14px; }
  .hero h1 { font-family: 'Space Grotesk', sans-serif; font-size: 34px; font-weight: 700; letter-spacing: -1px; margin-bottom: 12px; line-height: 1.1; }
  .hero h1 em { font-style: normal; color: var(--cyan); }
  .hero p { color: var(--muted); font-size: 14px; max-width: 540px; }
  .hero-stats { display: flex; gap: 28px; margin-top: 28px; padding-top: 24px; border-top: 1px solid var(--border); flex-wrap: wrap; }
  .hs-val { font-family: 'Space Grotesk', sans-serif; font-size: 26px; font-weight: 700; }
  .hs-label { font-size: 11px; color: var(--muted); margin-top: 2px; }

  .cat-header { margin-bottom: 24px; }
  .cat-eyebrow { font-family: 'JetBrains Mono', monospace; font-size: 10px; color: var(--muted); letter-spacing: 1.5px; text-transform: uppercase; margin-bottom: 6px; }
  .cat-title { font-family: 'Space Grotesk', sans-serif; font-size: 24px; font-weight: 700; letter-spacing: -0.5px; }
  .cat-ref { font-size: 12px; color: var(--muted); margin-top: 4px; font-family: 'JetBrains Mono', monospace; }
  .cat-ref span { color: var(--amber); }

  .qa-list { display: flex; flex-direction: column; gap: 10px; }
  .qa-card { background: var(--card); border: 1px solid var(--border); border-radius: 8px; overflow: hidden; transition: border-color 0.15s; }
  .qa-card:hover { border-color: var(--border-bright); }
  .qa-question { display: flex; align-items: flex-start; gap: 12px; padding: 14px 16px; cursor: pointer; user-select: none; }
  .qa-num { font-family: 'JetBrains Mono', monospace; font-size: 10px; color: var(--muted); background: rgba(255,255,255,0.05); padding: 2px 7px; border-radius: 3px; flex-shrink: 0; margin-top: 2px; min-width: 42px; text-align: center; }
  .qa-q-text { font-size: 14px; color: var(--white); flex: 1; line-height: 1.5; }
  .qa-chevron { font-size: 11px; color: var(--muted); flex-shrink: 0; margin-top: 3px; transition: transform 0.2s; }
  .qa-card.open .qa-chevron { transform: rotate(90deg); }
  .qa-answer { display: none; padding: 0 16px 16px 52px; border-top: 1px solid var(--border); }
  .qa-card.open .qa-answer { display: block; }
  .qa-answer-inner { padding-top: 12px; font-size: 13px; color: #9BAFC4; line-height: 1.7; }
  .qa-answer-inner strong { color: var(--white); font-weight: 600; }
  .qa-answer-inner .ref { display: inline-block; margin-top: 8px; font-family: 'JetBrains Mono', monospace; font-size: 10px; color: var(--amber); background: var(--amber-dim); border: 1px solid rgba(240,168,0,0.2); padding: 2px 8px; border-radius: 3px; letter-spacing: 0.5px; }

  .qa-card[data-type="eals"] .qa-num { color: var(--cyan); background: var(--cyan-dim); }
  .qa-card[data-type="radr"] .qa-num { color: var(--red); background: var(--red-dim); }
  .qa-card[data-type="bear"] .qa-num { color: var(--amber); background: var(--amber-dim); }
  .qa-card[data-type="rals"] .qa-num { color: var(--green); background: var(--green-dim); }
  .qa-card[data-type="maas"] .qa-num { color: var(--purple); background: var(--purple-dim); }

  .section-divider { display: flex; align-items: center; gap: 12px; margin: 28px 0 16px; }
  .section-divider-label { font-family: 'Space Grotesk', sans-serif; font-size: 13px; font-weight: 600; color: var(--white); white-space: nowrap; }
  .section-divider-line { flex: 1; height: 1px; background: var(--border); }

  .callout { border-radius: 7px; padding: 14px 16px; margin: 16px 0; border-left: 3px solid; font-size: 13px; }
  .callout.tip { background: var(--cyan-dim); border-color: var(--cyan); color: #A8D8E8; }
  .callout.warn { background: var(--amber-dim); border-color: var(--amber); color: #D4AA60; }
  .callout strong { color: var(--white); }

  .cat-nav { display: flex; justify-content: space-between; margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--border); }
  .nav-btn { font-family: 'Space Grotesk', sans-serif; font-size: 13px; font-weight: 600; padding: 10px 20px; border-radius: 7px; cursor: pointer; transition: all 0.12s; border: none; }
  .nav-btn.prev { background: transparent; border: 1px solid var(--border); color: var(--muted); }
  .nav-btn.prev:hover { color: var(--white); border-color: var(--border-bright); }
  .nav-btn.next { background: var(--cyan); color: var(--navy); }
  .nav-btn.next:hover { background: #22D8FF; }

  @media (max-width: 768px) {
    .sidebar { transform: translateX(-100%); transition: transform 0.25s; z-index: 150; }
    .sidebar.open { transform: translateX(0); }
    .main { margin-left: 0; padding: 20px 16px 80px; }
    .menu-btn { display: block; }
    .hero h1 { font-size: 24px; }
  }