:root {
    --primary: #7c1f1b;
    --alternate: #93731f;
    --bg: #f1e8d2;
    --bg-raised: #fbf6e9;
    --bg-deep: #e3d6b2;
    --ink: #2a2018;
    --ink-soft: #6b5c46;
    --line: rgba(42, 32, 24, .2);
    --code-bg: #2a1c16;
    --code-text: #f1e8d2;
    --code-muted: #a3927a;
    --code-string: #dd8f72;
    --code-keyword: #d9ab4a;
    --code-comment: #8c7c65;
    --shadow: 0 1px 2px rgba(42, 24, 16, 0.08), 0 8px 24px rgba(42, 24, 16, 0.10);
  }

  * { box-sizing: border-box; }

  body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: 'IBM Plex Sans', -apple-system, 'Segoe UI', sans-serif;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
  }

  a { color: var(--primary); }
  code, pre, .mono { font-family: 'IBM Plex Mono', ui-monospace, monospace; }

  code:not(pre code) {
    background: var(--bg-deep);
    border: 1px solid var(--line);
    padding: 0.1em 0.35em;
    font-size: 0.87em;
  }

  h1, h2, h3, h4 {
    font-family: 'Fraunces', Georgia, serif;
    font-weight: 480;
    letter-spacing: -0.01em;
  }

  /* Top bar */
  .topbar {
    position: sticky;
    top: 0;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 56px;
    padding: 0 16px;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--line);
  }
  .brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.02rem;
    color: var(--ink);
    text-decoration: none;
    font-family: 'Fraunces', Georgia, serif;
  }
  .brand .mark {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    background: var(--primary);
    border: 1px solid var(--alternate);
    color: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'Fraunces', Georgia, serif;
    font-style: italic;
    font-weight: 600;
    font-size: 0.9rem;
    line-height: 1;
  }
  .brand .sep {
    color: var(--alternate);
    font-weight: 500;
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.68rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
  }
  .topbar-links {
    display: flex;
    align-items: center;
    gap: 20px;
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.74rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
  }
  .topbar-links a { color: var(--ink-soft); text-decoration: none; }
  .topbar-links a:hover { color: var(--primary); }
  .menu-btn {
    display: none;
    background: transparent;
    border: 1px solid var(--line);
    color: var(--ink);
    padding: 6px 10px;
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.8rem;
    cursor: pointer;
  }

  /* Layout */
  .layout {
    display: grid;
    grid-template-columns: 260px minmax(0, 1fr);
    max-width: 1280px;
    margin: 0 auto;
  }

  /* Sidebar */
  aside.sidebar {
    position: sticky;
    top: 56px;
    align-self: start;
    height: calc(100vh - 56px);
    overflow-y: auto;
    padding: 24px 16px 40px;
    border-right: 1px solid var(--line);
  }
  .search-box {
    width: 100%;
    padding: 8px 10px;
    border: 1px solid var(--line);
    background: var(--bg-raised);
    color: var(--ink);
    font-family: 'IBM Plex Sans', -apple-system, 'Segoe UI', sans-serif;
    font-size: 0.85rem;
    margin-bottom: 16px;
  }
  .search-box:focus { outline: 2px solid var(--alternate); outline-offset: -1px; }
  .nav-group { margin-bottom: 4px; }
  .nav-group-title {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.68rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--alternate);
    margin: 18px 0 6px;
    padding: 0 10px;
  }
  .nav-group:first-of-type .nav-group-title { margin-top: 0; }
  nav.toc a {
    display: block;
    padding: 6px 10px;
    font-size: 0.87rem;
    color: var(--ink-soft);
    text-decoration: none;
    line-height: 1.35;
    border-left: 2px solid transparent;
  }
  nav.toc a:hover { background: var(--bg-deep); color: var(--ink); }
  nav.toc a.active {
    background: var(--bg-deep);
    color: var(--primary);
    border-left-color: var(--primary);
    font-weight: 600;
  }
  nav.toc a.sub {
    padding-left: 22px;
    font-size: 0.83rem;
  }
  nav.toc a[data-hidden="true"] { display: none; }

  /* Main content */
  main {
    min-width: 0;
    padding: 40px 32px 100px;
  }
  .content-wrap { max-width: 720px; }

  .page-kicker {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.76rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--alternate);
    margin: 0 0 10px;
  }
  h1.page-title {
    font-size: 2rem;
    margin: 0 0 12px;
  }
  .lede {
    color: var(--ink-soft);
    font-size: 1.02rem;
    max-width: 640px;
    margin: 0 0 8px;
  }

  section.doc-section {
    padding-top: 40px;
    margin-top: 24px;
    border-top: 1px solid var(--line);
    scroll-margin-top: 72px;
  }
  section.doc-section:first-of-type { border-top: none; }
  h2 {
    font-size: 1.4rem;
    margin: 0 0 12px;
    scroll-margin-top: 72px;
  }
  h3 {
    font-size: 1.05rem;
    margin: 28px 0 10px;
    scroll-margin-top: 72px;
  }
  h4 {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.8rem;
    margin: 22px 0 8px;
    color: var(--ink-soft);
    text-transform: uppercase;
    letter-spacing: 0.06em;
  }
  h2 .anchor, h3 .anchor {
    opacity: 0;
    text-decoration: none;
    color: var(--ink-soft);
    font-size: 0.85em;
    margin-left: 6px;
  }
  h2:hover .anchor, h3:hover .anchor { opacity: 1; }

  p { margin: 0 0 14px; color: var(--ink); }
  p.muted { color: var(--ink-soft); }

  pre.code {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 16px 18px;
    overflow-x: auto;
    font-size: 0.85rem;
    line-height: 1.6;
    box-shadow: var(--shadow);
    margin: 0 0 16px;
  }
  pre.code .kw { color: var(--code-keyword); }
  pre.code .str { color: var(--code-string); }
  pre.code .re { color: var(--code-string); opacity: 0.85; }
  pre.code .cm { color: var(--code-comment); font-style: italic; }
  pre.code .mut { color: var(--code-muted); }

  .callout {
    background: var(--bg-raised);
    border: 1px solid var(--line);
    border-left: 3px solid var(--primary);
    padding: 12px 16px;
    font-size: 0.92rem;
    color: var(--ink-soft);
    margin: 0 0 16px;
  }
  .callout strong { color: var(--ink); }

  .table-wrap {
    overflow-x: auto;
    margin: 0 0 16px;
  }
  .table-wrap .sig-table { margin: 0; }
  .sig-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.88rem;
    margin: 0 0 16px;
    background: var(--bg-raised);
    border: 1px solid var(--line);
  }
  .sig-table td {
    padding: 6px 10px;
    border-bottom: 1px solid var(--line);
    vertical-align: top;
  }
  .sig-table td:first-child {
    white-space: nowrap;
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    color: var(--primary);
  }

  .version-badge {
    display: inline-block;
    font-family: 'Fraunces', serif;
    font-style: italic;
    background: var(--bg-deep);
    color: var(--primary);
    font-weight: 600;
    font-size: 0.85rem;
    padding: 2px 12px;
    margin-right: 10px;
    vertical-align: middle;
  }
  .version-date {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    color: var(--ink-soft);
    font-size: 0.78rem;
    font-weight: 400;
    vertical-align: middle;
  }
  ul.changes { margin: 0 0 16px; padding-left: 20px; }
  ul.changes li { margin-bottom: 6px; }

  .prevnext {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid var(--line);
  }
  .prevnext a {
    flex: 1;
    text-decoration: none;
    border: 1px solid var(--line);
    padding: 12px 16px;
    color: var(--ink);
  }
  .prevnext a:hover { border-color: var(--primary); }
  .prevnext .label {
    display: block;
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.68rem;
    color: var(--ink-soft);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 4px;
  }
  .prevnext .next { text-align: right; }

  @media (max-width: 880px) {
    .layout { grid-template-columns: 1fr; }
    .menu-btn { display: inline-block; }
    aside.sidebar {
      position: fixed;
      top: 56px;
      left: 0;
      width: 280px;
      max-width: 85vw;
      background: var(--bg);
      z-index: 30;
      transform: translateX(-100%);
      transition: transform 0.18s ease;
      box-shadow: var(--shadow);
    }
    aside.sidebar.open { transform: translateX(0); }
    .sidebar-backdrop {
      display: none;
      position: fixed;
      inset: 56px 0 0 0;
      background: rgba(42, 24, 16, 0.35);
      z-index: 25;
    }
    .sidebar-backdrop.open { display: block; }
    main { padding: 32px 20px 80px; }
    .topbar-links a.hide-narrow { display: none; }
  }

  /* Specification page (ECMAScript-style numbered clauses) */
  .clause-num {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    color: var(--alternate);
    font-weight: 500;
    margin-right: 2px;
  }
  h4 .anchor { opacity: 0; text-decoration: none; color: var(--ink-soft); font-size: 0.85em; margin-left: 6px; }
  h4:hover .anchor { opacity: 1; }
  a.clause-ref { white-space: nowrap; }
  a.cite {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.85em;
    text-decoration: none;
    border-bottom: 1px dotted var(--line);
  }
  a.cite:hover { border-bottom-color: var(--primary); }
  .grammar {
    font-family: 'IBM Plex Mono', ui-monospace, monospace;
    font-size: 0.85rem;
    line-height: 1.7;
    background: var(--bg-raised);
    border: 1px solid var(--line);
    border-left: 3px solid var(--alternate);
    padding: 10px 16px;
    margin: 0 0 16px;
    overflow-x: auto;
  }
  .grammar em { color: var(--primary); font-style: italic; }
  .grammar code {
    background: transparent;
    border: none;
    padding: 0;
    color: var(--ink);
    font-weight: 600;
  }
  pre.code.grammar-block {
    background: var(--bg-raised);
    color: var(--ink);
    border: 1px solid var(--line);
    box-shadow: none;
  }
  .callout.spec-note { border-left-color: var(--alternate); }
  .callout.spec-note em { color: var(--ink); font-style: normal; font-weight: 600; }