/* ============================================================
     PRODUCT CRAFT BIBLE · INDIGO VARIANT
     Based on Musett Zok26 tokens, accent shifted to indigo
     ============================================================ */

  :root, [data-theme="light"] {
    --bg: #FAFAFA;
    --surface: #FEFEFE;
    --text: #080808;
    --text-2: #525252;
    --text-3: #9A9A9A;
    --accent: #4F46E5;
    --accent-light: #EEF2FF;
    --border: #E3E3E3;
    --shadow-sm: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
    --shadow-md: 0 4px 16px rgba(0,0,0,.10), 0 2px 4px rgba(0,0,0,.06);
    --shadow-lg: 0 12px 40px rgba(0,0,0,.15), 0 4px 12px rgba(0,0,0,.08);
    --radius: 10px;
    --font: 'Manrope', system-ui, -apple-system, sans-serif;
    --mono: 'Fira Code', 'JetBrains Mono', monospace;
    --hover-border: #9A9A9A;
    --hover-surface: #F4F4F4;
    --demo-bg: color-mix(in srgb, var(--text) 5%, transparent);
    --divider: color-mix(in srgb, var(--text) 5%, transparent);
    --danger-bg: #fef2f2;
    --danger-border: #fecaca;
    --danger-text: #991b1b;
    --danger-icon: #E24747;
    --success-bg: #f0fdf4;
    --success-border: #bbf7d0;
    --success-text: #166534;
    --success-icon: #15803d;
    --warning-bg: #fef9c3;
    --warning-border: #fde68a;
    --warning-text: #854d0e;
    --warning-icon: #eab308;
    color-scheme: light;
  }

  @media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
      --bg: #0A0A0A;
      --surface: #141414;
      --text: rgba(255,255,255,.92);
      --text-2: rgba(255,255,255,.65);
      --text-3: rgba(255,255,255,.45);
      --accent: #818CF8;
      --accent-light: rgba(79,70,229,.15);
      --border: rgba(255,255,255,.12);
      --shadow-sm: 0 1px 3px rgba(0,0,0,.25);
      --shadow-md: 0 4px 16px rgba(0,0,0,.35);
      --shadow-lg: 0 12px 40px rgba(0,0,0,.5);
      --hover-border: rgba(255,255,255,.25);
      --hover-surface: #1A1A1A;
      --demo-bg: color-mix(in srgb, var(--text) 5%, transparent);
      --divider: color-mix(in srgb, var(--text) 5%, transparent);
      --danger-bg: rgba(226,71,71,.12);
      --danger-border: rgba(226,71,71,.30);
      --danger-text: #fca5a5;
      --danger-icon: #F07575;
      --success-bg: rgba(34,197,94,.12);
      --success-border: rgba(34,197,94,.30);
      --success-text: #86efac;
      --success-icon: #22c55e;
      --warning-bg: rgba(234,179,8,.14);
      --warning-border: rgba(234,179,8,.30);
      --warning-text: #fcd34d;
      --warning-icon: #eab308;
      color-scheme: dark;
    }
  }

  [data-theme="dark"] {
    --bg: #0A0A0A;
    --surface: #141414;
    --text: rgba(255,255,255,.92);
    --text-2: rgba(255,255,255,.65);
    --text-3: rgba(255,255,255,.45);
    --accent: #818CF8;
    --accent-light: rgba(79,70,229,.15);
    --border: rgba(255,255,255,.12);
    --shadow-sm: 0 1px 3px rgba(0,0,0,.25);
    --shadow-md: 0 4px 16px rgba(0,0,0,.35);
    --shadow-lg: 0 12px 40px rgba(0,0,0,.5);
    --hover-border: rgba(255,255,255,.25);
    --hover-surface: #1A1A1A;
    --demo-bg: color-mix(in srgb, var(--text) 5%, transparent);
    --divider: color-mix(in srgb, var(--text) 5%, transparent);
    --danger-bg: rgba(226,71,71,.12);
    --danger-border: rgba(226,71,71,.30);
    --danger-text: #fca5a5;
    --danger-icon: #F07575;
    --success-bg: rgba(34,197,94,.12);
    --success-border: rgba(34,197,94,.30);
    --success-text: #86efac;
    --success-icon: #22c55e;
    --warning-bg: rgba(234,179,8,.14);
    --warning-border: rgba(234,179,8,.30);
    --warning-text: #fcd34d;
    --warning-icon: #eab308;
    color-scheme: dark;
  }

  * { margin: 0; padding: 0; box-sizing: border-box; }

  html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  body {
    font-family: var(--font);
    background: var(--surface);
    color: var(--text);
    line-height: 1.6;
    overflow-x: clip;
  }

  /* NAV */
  nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: color-mix(in srgb, var(--bg) 85%, transparent);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 12px 0;
  }
  nav .inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    gap: 12px;
  }
  nav .nav-actions {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: auto;
  }
  nav .logo {
    font-weight: 700;
    color: var(--text);
    font-size: 15px;
    letter-spacing: -0.02em;
    display: inline-flex;
    align-items: center;
    gap: 8px;
  }
  .logo-icon {
    width: 23px;
    height: 23px;
    stroke: var(--accent);
    stroke-width: 1.8;
    fill: none;
    stroke-linecap: round;
    stroke-linejoin: round;
    flex-shrink: 0;
  }

  .nav-current-section {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-3);
    margin-left: 16px;
    padding-left: 16px;
    border-left: 1px solid var(--border);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 300px;
    transition: color 300ms;
  }
  .nav-current-section.visible {
    color: var(--text-2);
  }
  .nav-current-section .nav-section-num {
    color: var(--accent);
    font-weight: 700;
    margin-right: 6px;
  }
  .nav-current-section .nav-crumb-sep { margin: 0 7px; color: var(--text-3); font-weight: 400; }
  @media (max-width: 899.98px) {
    .nav-current-section { display: none; }
  }

  /* HEADER */
  header {
    max-width: 1100px;
    margin: 0 auto;
    padding: 80px 24px 48px;
  }
  header h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.1;
    text-wrap: balance;
    margin-bottom: 16px;
  }
  header p {
    font-size: 18px;
    color: var(--text-2);
    max-width: 60ch;
    text-wrap: pretty;
  }
  .hero-card {
    max-width: 900px;
    background: var(--surface);
    border-radius: 16px;
    padding: 40px;
    outline: 1px solid var(--border);
    outline-offset: -1px;
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
  }
  .hero-card::before { display: none; }
  .source-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 24px;
  }
  .source-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 999px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-2);
    text-decoration: none;
    transition: border-color 150ms, color 150ms;
  }
  .source-tag:hover { border-color: var(--accent); color: var(--accent); }

  /* MAIN */
  main {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px 120px;
  }

  /* PART DIVIDERS */
  .part-divider {
    margin-top: 80px;
    margin-bottom: 32px;
    padding-top: 32px;
    border-top: 1px solid var(--border);
    text-align: center;
  }
  .part-label {
    display: block;
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--accent);
    margin-bottom: 8px;
    font-variant: small-caps;
  }
  .part-divider h2 {
    font-size: 28px;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
  }
  .part-divider p {
    font-size: 15px;
    color: var(--text-2);
  }

  /* SECTION */
  .section {
    margin-top: 64px;
  }
  .section-header {
    display: flex;
    align-items: baseline;
    gap: 12px;
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
  }
  .section-number {
    font-size: 20px;
    font-weight: 700;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
    letter-spacing: -0.02em;
  }
  .section h2 {
    font-size: 24px;
    font-weight: 700;
    letter-spacing: -0.02em;
  }
  .section-count {
    font-size: 13px;
    color: var(--text-3);
    margin-left: auto;
  }

  /* CARDS */
  .rules-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .rule {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 20px 24px;
    min-width: 0;
    box-shadow: var(--shadow-sm);
    outline: 1px solid var(--border);
    outline-offset: -1px;
    transition: box-shadow 200ms cubic-bezier(.2,.8,.2,1), outline-color 200ms, background 200ms;
    scroll-margin-top: 80px;
    /* Con 1000+ reglas la página supera 800.000px de alto. content-visibility evita
       layout/paint/animación de las reglas fuera del viewport, eliminando el jank de
       carga y el render roto a media carga. El navegador recuerda la altura real tras
       el primer render; 640px es solo la estimación inicial. */
    content-visibility: auto;
    contain-intrinsic-size: auto 640px;
  }
  .rule:hover {
    box-shadow: var(--shadow-md);
    outline-color: var(--hover-border);
    background: var(--hover-surface);
  }
  @keyframes rule-pulse {
    0%   { outline-color: var(--accent); box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent) 35%, transparent); }
    50%  { outline-color: var(--accent); box-shadow: 0 0 0 6px color-mix(in srgb, var(--accent) 0%, transparent); }
    100% { outline-color: var(--border); box-shadow: var(--shadow-sm); }
  }
  .rule-highlight {
    animation: rule-pulse 2.2s cubic-bezier(.2,.8,.2,1) forwards;
    outline-width: 2px;
  }
  @media (prefers-reduced-motion: reduce) {
    .rule-highlight { animation: none; outline-color: var(--accent); outline-width: 2px; }
  }
  .rule-head {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 8px;
  }
  .rule-num {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    display: grid;
    place-items: center;
    border-radius: 8px;
    background: var(--accent-light);
    color: var(--accent);
    font-size: 12px;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
  }
  .rule h3 {
    font-size: 15px;
    font-weight: 600;
    line-height: 1.4;
    letter-spacing: -0.01em;
    padding-top: 4px;
  }
  .rule p {
    font-size: 14px;
    color: var(--text-2);
    line-height: 1.6;
    text-wrap: pretty;
  }
  .rule code {
    font-family: var(--mono);
    font-size: 12px;
    background: var(--accent-light);
    color: var(--accent);
    padding: 2px 6px;
    border-radius: 4px;
  }
  .rule .source {
    display: inline-block;
    margin-top: 8px;
    font-size: 11px;
    color: var(--text-3);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
  }

  /* CODE BLOCKS */
  .code-block {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px 16px;
    margin-top: 10px;
    overflow-x: auto;
    font-family: var(--mono);
    font-size: 12px;
    line-height: 1.7;
    color: var(--text-2);
  }

  /* EXAMPLES */
  .example-pair {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1px;
    background: var(--border);
    border-radius: 12px;
    overflow: hidden;
    min-width: 0;
    margin-top: 12px;
  }
  @media (max-width: 540px) {
    .example-pair { grid-template-columns: 1fr; }
  }
  .example {
    background: var(--bg);
    padding: 20px 22px;
    font-size: 13px;
    line-height: 1.5;
    display: flex;
    flex-direction: column;
  }
  .example.good {
    background: color-mix(in srgb, #15803d 3%, var(--bg));
  }
  .example.bad {
    background: color-mix(in srgb, #E24747 3%, var(--bg));
  }
  .example .annotation {
    margin-top: auto;
  }

  /* Panel header: icon + descriptive label */
  .panel-head {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 14px;
  }
  .panel-icon {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 10px;
    color: #fff;
    flex-shrink: 0;
    font-weight: 700;
    line-height: 1;
  }
  .bad .panel-icon { background: #E24747; }
  .good .panel-icon { background: #15803d; }
  [data-theme="dark"] .good .panel-icon { background: #15803d; }
  .panel-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-2);
  }

  /* Demo area */
  .example .demo {
    font-family: var(--font);
    color: var(--text);
    flex: 1;
    min-width: 0;
    padding: 20px;
    display: flex;
    flex-direction: column;
    justify-content: center;
  }

  /* Color/depth/borders demos: inherit theme bg (no forced light) */

  /* Annotation: input-style box with dot */
  .example .annotation {
    font-size: 11px;
    color: var(--text-2);
    margin-top: 14px;
    padding: 8px 10px 8px 22px;
    background: var(--demo-bg);
    border: 1px solid var(--divider);
    border-radius: 6px;
    line-height: 1.5;
    position: relative;
  }
  .example .annotation::before {
    content: "";
    position: absolute;
    left: 9px;
    top: 50%;
    transform: translateY(-50%);
    width: 5px;
    height: 5px;
    border-radius: 50%;
  }
  .bad .annotation::before { background: #E24747; }
  .good .annotation::before { background: #15803d; }
  [data-theme="dark"] .good .annotation::before { background: #22c55e; }


  /* Replay button for animations */
  .example .replay-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin-top: 12px;
    padding: 6px 14px;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 11px;
    font-weight: 600;
    font-family: var(--font);
    cursor: pointer;
    transition: opacity 150ms;
  }
  .example .replay-btn:hover { opacity: .85; }

  /* Property tag */
  .example .prop {
    font-family: var(--mono);
    font-size: 10px;
    color: var(--text-3);
    background: var(--demo-bg);
    padding: 2px 6px;
    border-radius: 3px;
    margin-top: 8px;
    display: inline-block;
  }

  /* Demo utility classes */
  .d-box {
    background: var(--demo-bg);
    padding: 10px 14px;
    border-radius: 6px;
    font-size: 13px;
    color: var(--text);
  }
  .d-code {
    font-family: var(--mono);
    font-size: 11px;
    line-height: 1.7;
    color: var(--text);
  }
  .d-code .hl-bad { color: #ef4444; font-weight: 600; }
  .d-code .hl-good { color: #15803d; font-weight: 600; }
  .d-code .hl-muted { color: var(--text-3); }
  .d-btn {
    display: inline-flex;
    align-items: center;
    padding: 7px 18px;
    border-radius: 8px;
    font-size: 12px;
    font-weight: 500;
  }
  .d-btn-primary { background: var(--accent); color: #fff; }
  .d-btn-outline { border: 1px solid var(--border); color: var(--text); background: transparent; }
  .d-btn-ghost { color: var(--text-2); background: transparent; }
  .d-tag {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 11px;
  }
  .d-caption {
    font-size: 11px;
    color: var(--text-2);
    margin-top: 4px;
  }

  /* PHILOSOPHY */
  .philosophy {
    background: var(--surface);
    border-radius: 16px;
    padding: 40px;
    margin-top: 64px;
    box-shadow: var(--shadow-lg);
    outline: 1px solid var(--border);
    outline-offset: -1px;
  }
  .philosophy h2 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 20px;
  }
  .philosophy blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 16px;
    margin: 16px 0;
    font-size: 15px;
    color: var(--text-2);
    font-style: italic;
  }

  /* ANTI-PATTERNS */
  .anti {
    border-left: 3px solid #ef4444;
  }
  .anti .rule-num {
    background: #fef2f2;
    color: #ef4444;
  }
  @media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .anti .rule-num {
      background: #450a0a;
      color: #fca5a5;
    }
    :root:not([data-theme="light"]) .example.good {
      background: color-mix(in srgb, #22c55e 4%, var(--bg));
    }
    :root:not([data-theme="light"]) .example.bad {
      background: color-mix(in srgb, #ef4444 4%, var(--bg));
    }
  }
  [data-theme="dark"] .anti .rule-num {
    background: #450a0a;
    color: #fca5a5;
  }
  [data-theme="dark"] .example.good {
    background: color-mix(in srgb, #22c55e 4%, var(--bg));
  }
  [data-theme="dark"] .example.bad {
    background: color-mix(in srgb, #ef4444 4%, var(--bg));
  }

  /* RULE CARDS: clickable, accent border on hover */
  .rule {
    position: relative;
    cursor: pointer;
  }
  .rule.fade-ready {
    opacity: 0;
    transform: translateY(12px);
  }
  .rule.fade-ready.in-view {
    opacity: 1;
    transform: translateY(0);
    transition: opacity 400ms cubic-bezier(.2,.8,.2,1),
                transform 400ms cubic-bezier(.2,.8,.2,1),
                box-shadow 200ms cubic-bezier(.2,.8,.2,1),
                outline-color 200ms,
                background 200ms;
  }
  @media (prefers-reduced-motion: reduce) {
    .rule.fade-ready { opacity: 1; transform: none; }
    .rule.fade-ready.in-view { transition: box-shadow 200ms, outline-color 200ms, background 200ms; }
  }
  .rule:hover {
    outline-color: var(--accent);
  }
  .rule.rule-active {
    outline-color: var(--accent);
    outline-width: 2px;
    box-shadow: var(--shadow-md), 0 0 0 4px color-mix(in srgb, var(--accent) 8%, transparent);
  }
  .rule-info-btn {
    display: none;
  }
  .rule-head .rule-chevron {
    flex-shrink: 0;
    margin-left: auto;
    width: 24px;
    height: 24px;
    padding: 4px;
    border-radius: 6px;
    background: var(--accent-light);
    color: var(--accent);
    transform: translateX(0);
    transition: transform 200ms, background 200ms;
    margin-top: 2px;
  }
  .rule:hover .rule-head .rule-chevron {
    transform: translateX(2px);
    background: color-mix(in srgb, var(--accent) 20%, transparent);
  }

  /* DETAIL DRAWER */
  .detail-drawer-backdrop {
    position: fixed;
    inset: 0;
    z-index: 300;
    background: transparent;
    display: none;
    opacity: 0;
    transition: opacity 250ms;
    pointer-events: none;
  }
  .detail-drawer-backdrop.open {
    display: block;
    opacity: 1;
    pointer-events: auto;
  }
  .detail-drawer {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    z-index: 301;
    width: min(520px, 100vw - 32px);
    background: var(--surface);
    border-left: 1px solid var(--border);
    box-shadow: -8px 0 32px rgba(0,0,0,.08);
    transform: translateX(100%);
    transition: transform 250ms cubic-bezier(.2,.8,.2,1);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    visibility: hidden;
  }
  .detail-drawer.open {
    visibility: visible;
  }
  .detail-drawer.open {
    transform: translateX(0);
  }
  /* ─── DRAWER: TABLET & MOBILE (≤1024px) ─── */
  @media (max-width: 1024px) {
    .detail-drawer {
      top: auto;
      left: 0;
      right: 0;
      bottom: 0;
      width: 100%;
      height: 90vh;
      border-left: none;
      border-top: 1px solid var(--border);
      border-radius: 20px 20px 0 0;
      box-shadow: none;
      transform: translateY(100%);
    }
    .detail-drawer.open {
      box-shadow: 0 -12px 48px rgba(0,0,0,.15) !important;
    }
    .detail-drawer.open {
      transform: translateY(0);
    }

    /* Drag handle visible — taller grab hotspot */
    .detail-drawer-handle {
      display: flex !important;
      justify-content: center;
      align-items: center;
      padding: 14px 0 18px;
    }
    .detail-drawer-handle-bar {
      width: 40px;
      height: 5px;
      background: var(--text-3);
      border-radius: 3px;
      opacity: 0.4;
    }

    /* Header layout - fixed height, doesn't grow */
    .detail-drawer-header {
      order: 1;
      padding: 0 !important;
      border-bottom: 1px solid var(--border) !important;
      flex-shrink: 0 !important;
    }

    /* Hide desktop toolbar entirely (nav moved to footer) */
    .detail-drawer-toolbar {
      display: none !important;
    }

    /* Close X stays top-right; header is the drag zone for the handle gesture */
    .detail-drawer-header { touch-action: none; }
    .detail-drawer-close {
      top: 12px !important;
      right: 12px !important;
      width: 44px !important;
      height: 44px !important;
    }
    /* Handle is now interactive (drag to dismiss) */
    .detail-drawer-handle { cursor: grab; }
    .detail-drawer-handle:active { cursor: grabbing; }

    /* Meta section - centered, below drag handle, with top spacing */
    .detail-drawer-meta {
      padding: 20px 24px 16px !important;
      text-align: center !important;
      align-items: center !important;
      gap: 2px !important;
    }
    .detail-drawer-meta h3 {
      font-size: 18px;
    }
    .detail-section-label {
      font-size: 11px;
    }

    /* Body content - scrollable, takes remaining space */
    .detail-drawer-body {
      padding: 24px !important;
      order: 2;
      flex: 1 !important;
      overflow-y: auto !important;
      min-height: 0 !important;
    }

    /* ─── FOOTER NAV BAR (thumb zone) ─── */
    .detail-drawer-footer-nav {
      display: flex !important;
      flex-shrink: 0 !important;
    }
  }

  /* Footer nav bar: hidden on desktop, shown on tablet/mobile */
  .detail-drawer-footer-nav {
    display: none;
    flex-direction: column;
    flex-shrink: 0;
    order: 3;
    background: var(--surface);
  }
  .detail-drawer-handle {
    display: none;
  }
  .detail-footer-spacer {
    display: none;
  }
  /* Nav row: centered with 24px gap */
  .detail-footer-nav-row {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 24px;
    padding: 16px 24px;
    border-top: 1px solid var(--border);
  }
  .detail-nav-btn-lg {
    width: 48px;
    height: 48px;
    border: none;
    background: var(--demo-bg);
    color: var(--text-2);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    transition: background 120ms, color 120ms;
  }
  .detail-nav-btn-lg:hover {
    background: var(--accent-light);
    color: var(--accent);
  }
  .detail-nav-btn-lg:active {
    transform: scale(0.97);
  }
  .detail-nav-num-lg {
    font-size: 18px;
    font-weight: 700;
    color: var(--accent);
    min-width: 40px;
    text-align: center;
    font-variant-numeric: tabular-nums;
  }
  /* Close button: full width below divider */
  .detail-close-row {
    padding: 12px 24px;
    padding-bottom: calc(12px + env(safe-area-inset-bottom, 0px));
    border-top: 1px solid var(--border);
  }
  .detail-close-lg {
    width: 100%;
    height: 48px;
    background: none;
    border: 1px solid var(--border);
    color: var(--text-2);
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: var(--font);
    font-size: 14px;
    font-weight: 600;
    transition: background 120ms, color 120ms, border-color 120ms;
  }
  .detail-close-lg:hover {
    background: var(--demo-bg);
    color: var(--text);
  }
  .detail-close-lg:active {
    transform: scale(0.98);
  }

  /* Phone-specific refinements */
  @media (max-width: 480px) {
    .detail-drawer {
      height: 94vh;
      border-radius: 16px 16px 0 0;
    }
    .detail-drawer-meta {
      padding: 0 20px 16px;
    }
    .detail-drawer-meta h3 {
      font-size: 16px;
    }
    .detail-drawer-body {
      padding: 20px;
    }
    .detail-drawer-footer-nav {
      padding: 12px 16px;
      padding-bottom: calc(12px + env(safe-area-inset-bottom, 0px));
      gap: 12px;
    }
    .detail-drawer-footer-nav .detail-nav-group {
      padding: 4px;
      border-radius: 12px;
    }
    .detail-drawer-footer-nav .detail-nav-btn {
      width: 48px;
      height: 44px;
    }
    .detail-drawer-footer-nav .detail-drawer-close {
      width: 44px;
      height: 44px;
      border-radius: 12px;
    }
  }
  .detail-drawer-header {
    position: relative;
    display: flex;
    flex-direction: column;
    padding: 0;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
  }
  .detail-drawer-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 16px;
  }
  .detail-drawer-meta {
    padding: 0 24px 16px;
    display: flex;
    flex-direction: column;
    gap: 4px;
  }
  .detail-drawer-header h3 {
    font-size: 16px;
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: -0.01em;
  }
  .detail-section-label {
    font-size: 10px;
    font-weight: 600;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.06em;
  }
  .detail-nav-group {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--demo-bg);
    border-radius: 12px;
    padding: 4px 8px;
  }
  .detail-nav-btn {
    width: 44px;
    height: 44px;
    border: none;
    background: var(--demo-bg);
    color: var(--text-2);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    transition: background 120ms, color 120ms;
  }
  .detail-nav-btn svg {
    display: block;
    width: 18px;
    height: 18px;
  }
  .detail-nav-btn:hover {
    background: var(--accent-light);
    color: var(--accent);
  }
  .detail-nav-num {
    font-size: 15px;
    font-weight: 700;
    color: var(--accent);
    min-width: 36px;
    text-align: center;
    font-variant-numeric: tabular-nums;
    line-height: 44px;
  }
  .detail-drawer-close {
    position: absolute;
    top: 14px;
    right: 16px;
    z-index: 4;
    width: 40px;
    height: 40px;
    border: none;
    background: var(--demo-bg);
    color: var(--text-2);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    font-size: 14px;
    font-family: var(--font);
    transition: background 120ms, color 120ms;
    flex-shrink: 0;
  }
  .detail-drawer-close:hover {
    background: color-mix(in srgb, var(--danger-icon) 10%, transparent);
    color: var(--danger-icon);
  }
  .detail-drawer-body {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
  }
  .detail-drawer-body::-webkit-scrollbar { width: 4px; }
  .detail-drawer-body::-webkit-scrollbar-thumb { background: var(--border); border-radius: 999px; }

  .detail-source-ref {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    padding: 8px 12px;
    background: var(--accent-light);
    border-radius: 8px;
    margin-bottom: 16px;
    color: var(--text-2);
    line-height: 1.6;
  }
  .detail-source-ref a {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 150ms;
  }
  .detail-source-ref a:hover {
    border-bottom-color: var(--accent);
  }



  .detail-cheatsheet {
    margin-top: 20px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
  }
  .detail-cheatsheet h4 {
    margin-top: 0 !important;
  }
  .cheatsheet-box {
    background: var(--demo-bg);
    border-radius: 8px;
    padding: 12px;
    font-family: var(--mono);
    font-size: 12px;
    line-height: 1.8;
  }
  .cheatsheet-row {
    display: flex;
    justify-content: space-between;
    gap: 12px;
  }
  .cheatsheet-key {
    color: var(--text-2);
    white-space: nowrap;
  }
  .cheatsheet-val {
    color: var(--accent);
    font-weight: 600;
    text-align: right;
  }
  .cheatsheet-scale {
    color: var(--accent);
    font-weight: 600;
    text-align: center;
    letter-spacing: 0.02em;
  }

  .detail-see-example {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-top: 16px;
    padding: 8px 16px;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 12px;
    font-weight: 600;
    font-family: var(--font);
    cursor: pointer;
    transition: opacity 150ms;
    width: 100%;
    justify-content: center;
  }
  .detail-see-example:hover { opacity: .85; }

  .detail-drawer-body h4 {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-3);
    margin-top: 24px;
    margin-bottom: 8px;
  }
  .detail-drawer-body h4:first-child { margin-top: 0; }
  .detail-drawer-body p {
    font-size: 14px;
    color: var(--text-2);
    line-height: 1.65;
    margin-bottom: 12px;
  }
  .detail-drawer-body ul {
    padding-left: 18px;
    margin-bottom: 12px;
  }
  .detail-drawer-body li {
    font-size: 14px;
    color: var(--text-2);
    line-height: 1.65;
    margin-bottom: 6px;
  }
  .detail-drawer-body code {
    font-family: var(--mono);
    font-size: 12px;
    background: var(--demo-bg, rgba(0,0,0,.04));
    color: var(--accent);
    padding: 2px 6px;
    border-radius: 4px;
  }
  .detail-drawer-body .source-label {
    font-size: 11px;
    color: var(--text-3);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 500;
    margin-top: 24px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
  }

  /* SIDEBAR — shared visual styles (all viewports); phone default = off-canvas drawer */
  .sidebar {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    width: min(86vw, 320px);
    height: 100vh;
    background: var(--bg);
    border-right: 1px solid var(--border);
    z-index: 200;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    transform: translateX(-100%);
    transition: transform .28s ease;
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-backdrop {
    position: fixed;
    inset: 0;
    z-index: 190;
    background: rgba(0,0,0,.4);
    opacity: 0;
    visibility: hidden;
    transition: opacity .28s ease, visibility .28s ease;
  }
  .sidebar-backdrop.open { opacity: 1; visibility: visible; }
  .nav-menu {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    padding: 0;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-2);
    cursor: pointer;
    transition: border-color 150ms, color 150ms;
  }
  .nav-menu:hover { border-color: var(--accent); color: var(--accent); }
  .nav-menu svg { width: 18px; height: 18px; stroke: currentColor; stroke-width: 2; fill: none; stroke-linecap: round; }
  .sidebar-close {
    position: absolute;
    top: 12px;
    right: 12px;
    width: 44px;
    height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--text-2);
    font-size: 20px;
    line-height: 1;
    cursor: pointer;
  }
  .sidebar-close:hover { background: var(--hover-surface); color: var(--text); }
  .sb-empty {
    display: none;
    padding: 18px 10px;
    font-size: 12px;
    color: var(--text-3);
    text-align: center;
  }
  .sb-empty.show { display: block; }
  /* internal sidebar styles below apply at all viewports */
  .sidebar-header {
    padding: 72px 8px 0;
    flex-shrink: 0;
  }
    .sidebar-header .logo {
      font-weight: 700;
      font-size: 15px;
      letter-spacing: -0.02em;
      color: var(--text);
      display: block;
      margin-bottom: 16px;
    }
    .sidebar-search {
      position: relative;
      margin-top: 12px;
      margin-bottom: 12px;
    }
    .sidebar-search input {
      width: 100%;
      padding: 8px 12px 8px 32px;
      border: 1px solid var(--border);
      border-radius: 8px;
      background: var(--surface);
      color: var(--text);
      font-family: var(--font);
      font-size: 12px;
      line-height: 1;
      outline: none;
      transition: border-color 150ms;
    }
    .sidebar-search input:focus { border-color: var(--accent); }
    .sidebar-search input::placeholder { color: var(--text-3); }
    .sidebar-search .sb-icon {
      position: absolute;
      left: 10px;
      top: 50%;
      transform: translateY(-50%);
      width: 13px;
      height: 13px;
      color: var(--text-3);
      display: flex;
      align-items: center;
    }
    .sidebar-search .sb-icon svg {
      width: 13px;
      height: 13px;
      stroke: currentColor;
      stroke-width: 2;
      fill: none;
      stroke-linecap: round;
      stroke-linejoin: round;
    }

    /* Search autocomplete dropdown - fixed to avoid sidebar overflow clip */
    .sb-search-dropdown {
      position: fixed;
      left: 12px;
      right: auto;
      width: 236px;
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: 10px;
      box-shadow: 0 12px 40px rgba(0,0,0,.18), 0 4px 12px rgba(0,0,0,.1);
      z-index: 200;
      max-height: 340px;
      overflow-y: auto;
      padding: 6px;
    }
    .sb-search-dropdown::-webkit-scrollbar { width: 4px; }
    .sb-search-dropdown::-webkit-scrollbar-thumb { background: var(--border); border-radius: 999px; }
    .sb-search-item {
      display: flex;
      align-items: center;
      gap: 10px;
      padding: 8px 12px;
      cursor: pointer;
      border-radius: 8px;
      transition: background 100ms;
    }
    .sb-search-item:hover, .sb-search-item.selected {
      background: var(--accent-light);
    }
    .sb-search-item-num {
      font-size: 11px;
      font-weight: 700;
      color: #fff;
      background: var(--accent);
      min-width: 30px;
      height: 22px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: 6px;
      font-variant-numeric: tabular-nums;
      flex-shrink: 0;
      letter-spacing: -0.01em;
    }
    .sb-search-item-title {
      font-size: 12px;
      font-weight: 500;
      color: var(--text);
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
      flex: 1;
    }
    .sb-search-item.selected .sb-search-item-title {
      color: var(--accent);
      font-weight: 600;
    }
    .sidebar-nav {
      flex: 1;
      min-height: 0;
      overflow-y: auto;
      padding: 0 12px 24px;
      scrollbar-width: thin;
      scrollbar-color: var(--border) transparent;
    }
    .sidebar-nav::-webkit-scrollbar { width: 3px; }
    .sidebar-nav::-webkit-scrollbar-thumb { background: var(--border); border-radius: 999px; }
    .sb-group {
      margin-bottom: 12px;
    }
    .sb-group-label {
      font-size: 10px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--text-3);
      padding: 16px 8px 4px;
      margin-bottom: 2px;
    }
    .sb-group:first-child .sb-group-label {
      padding-top: 6px;
    }
    .sb-divider {
      height: 1px;
      background: var(--border);
      margin: 12px 8px;
    }
    .sb-link {
      display: flex;
      align-items: center;
      gap: 8px;
      padding: 5px 8px;
      margin-bottom: 4px;
      border: 1px solid transparent;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 500;
      color: var(--text-2);
      text-decoration: none;
      transition: background 100ms, color 100ms, border-color 100ms;
    }
    .sb-link:hover { background: var(--accent-light); color: var(--text); }
    .sb-link.active {
      background: var(--accent-light);
      color: var(--accent);
      font-weight: 600;
      border-color: color-mix(in srgb, var(--accent) 35%, transparent);
    }
    .sb-link.hidden { display: none; }
    .sb-group.hidden { display: none; }
    .sb-num {
      flex-shrink: 0;
      width: 22px;
      height: 22px;
      display: grid;
      place-items: center;
      border-radius: 6px;
      font-size: 10px;
      font-weight: 700;
      font-variant-numeric: tabular-nums;
      background: var(--accent-light);
      color: var(--accent);
    }
    .sb-link.active .sb-num {
      background: var(--accent);
      color: #fff;
    }
    .sb-range {
      margin-left: auto;
      flex-shrink: 0;
      white-space: nowrap;
      font-size: 10px;
      font-weight: 400;
      color: var(--text-3);
      font-variant-numeric: tabular-nums;
      opacity: 0.7;
    }
    .sb-home {
      margin-top: 8px;
      margin-bottom: -4px;
    }
    .sb-philosophy {
      padding: 12px 8px 0;
      border-top: 1px solid var(--border);
      margin-top: 8px;
    }
    .sb-philosophy a {
      font-size: 12px;
      color: var(--text-3);
      text-decoration: none;
    }
    .sb-philosophy a:hover { color: var(--text-2); }
    .sidebar-footer {
      flex-shrink: 0;
      border-top: 1px solid var(--border);
      padding: 12px 20px 8px;
    }
    .sb-kbd-hint {
      padding: 0;
      display: flex;
      flex-direction: column;
      gap: 6px;
    }
    .sb-kbd-row {
      display: flex;
      align-items: center;
      gap: 7px;
      font-size: 10px;
      color: var(--text-3);
    }
    .sb-keys { display: inline-flex; gap: 3px; }
    .sb-kbd {
      min-width: 16px;
      height: 16px;
      padding: 0 4px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: 1px solid var(--border);
      border-radius: 4px;
      background: var(--demo-bg);
      font-family: var(--font);
      font-size: 10px;
      line-height: 1;
      color: var(--text-2);
    }
    .sb-kbd-note {
      font-size: 9px;
      color: var(--text-3);
      opacity: 0.8;
      padding-left: 1px;
    }

  /* PERSISTENT SIDEBAR — tablet + desktop (>=900px) */
  @media (min-width: 900px) {
    .sidebar {
      width: 290px;
      z-index: 90;
      transform: none;
      transition: none;
      box-shadow: none;
    }
    .sidebar-backdrop { display: none; }
    .detail-drawer-backdrop { left: 290px; }
    .nav-menu { display: none; }
    .sidebar-close { display: none; }
    .sidebar-header .logo { display: none; }

    nav { padding-left: 0; }
    nav .inner {
      max-width: none;
      margin: 0;
      padding: 0 32px;
      justify-content: flex-start;
    }
    header {
      max-width: none;
      margin: 0;
      padding: 64px 48px 40px 314px;
    }
    main {
      max-width: none;
      margin: 0;
      padding: 0 48px 120px 314px;
    }
    footer {
      max-width: none;
      margin: 0;
      padding: 24px 48px 24px 314px;
      text-align: left;
    }
    .part-divider { display: none; }
    .rules-grid { max-width: 900px; }
    .section-header { max-width: 900px; }
    .hero-card { max-width: 900px; }
    header h1, header p, .source-grid { max-width: 700px; }
  }

  /* PHONE DRAWER — touch sizing (<900px) */
  @media (max-width: 899.98px) {
    .sidebar-header { padding: 16px 60px 0 20px; }
    .sidebar-search input { font-size: 16px; padding: 12px 12px 12px 34px; }
    .sb-link { padding: 11px 10px; min-height: 44px; }
    .sb-num { width: 24px; height: 24px; }
    .sb-group-label { padding-top: 14px; }
  }

  /* SKIP-LINK (R98, WCAG 2.4.1): first focusable, visible only on focus */
  .skip-link {
    position: absolute;
    left: -9999px;
    top: 0;
    z-index: 9999;
    background: var(--accent);
    color: #fff;
    padding: 10px 16px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    font-family: var(--font);
    font-size: 14px;
  }
  .skip-link:focus,
  .skip-link:focus-visible {
    position: fixed;
    left: 12px;
    top: 12px;
    outline: 2px solid #fff;
    outline-offset: 2px;
  }

  /* Defensive :focus-visible ring for interactive elements without their own (R253) */
  a:focus-visible,
  button:focus-visible,
  [tabindex]:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
  }
  main:focus { outline: none; }

  /* prefers-reduced-motion: kill animations + smooth scroll (R109, R261, R334, R484) */
  @media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
      animation-duration: 0.01ms !important;
      animation-iteration-count: 1 !important;
      transition-duration: 0.01ms !important;
      scroll-behavior: auto !important;
    }
  }

  /* THEME TOGGLE */
  .theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    padding: 0;
    margin-left: auto;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    color: var(--text-2);
    transition: border-color 150ms, color 150ms, background 150ms;
  }
  .theme-toggle:hover {
    border-color: var(--hover-border);
    color: var(--text);
  }
  .theme-icon {
    width: 16px;
    height: 16px;
    stroke: currentColor;
    stroke-width: 2;
    fill: none;
    stroke-linecap: round;
    stroke-linejoin: round;
    display: none;
  }
  /* Show correct icon based on resolved theme */
  [data-theme="light"] .theme-icon.sun { display: block; }
  [data-theme="dark"] .theme-icon.moon { display: block; }
  .theme-icon.system { display: block; }
  [data-theme="light"] .theme-icon.system,
  [data-theme="dark"] .theme-icon.system { display: none; }
  .theme-icon.moon { fill: currentColor; stroke: none; }

  /* FOOTER */
  footer {
    max-width: 1100px;
    margin: 0 auto;
    padding: 24px;
    text-align: center;
    font-size: 13px;
    color: var(--text-3);
    border-top: 1px solid var(--border);
  }

  @media (max-width: 640px) {
    header { padding: 48px 16px 32px; }
    main { padding: 0 16px 80px; }
    .rule { padding: 16px; }
    .philosophy { padding: 24px; }
    .section { margin-top: 48px; }
  }

/* Cross-reference links inside rule prose */
.rule-xref {
  display: inline-block;
  padding: 0 4px;
  margin: 0 1px;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
  border-radius: 3px;
  background: color-mix(in srgb, var(--accent) 8%, transparent);
  transition: background 0.15s ease;
}
.rule-xref:hover {
  background: color-mix(in srgb, var(--accent) 16%, transparent);
  text-decoration: underline;
}