/* ─────────────────────────────────────────────
       HEADER
    ───────────────────────────────────────────── */
    .header {
      position: fixed;
      top: 0; left: 0; right: 0;
      height: var(--header-h);
      background: rgba(8, 8, 16, 0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border);
      display: flex;
      align-items: center;
      padding: 0 1.25rem;
      z-index: 100;
      gap: 1rem;
    }
    .header-logo {
      display: flex;
      align-items: center;
      gap: 0.6rem;
      text-decoration: none;
      flex-shrink: 0;
      min-width: var(--sidebar-w);
    }
    .logo-mark {
      width: 32px;
      height: 32px;
      background: linear-gradient(135deg, var(--gold-light), var(--gold));
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-family: var(--font-head);
      font-weight: 700;
      font-size: 14px;
      color: var(--bg); /* dark glyph reads clearly on the gold mark */
      flex-shrink: 0;
    }
    .logo-text {
      font-family: var(--font-head);
      font-weight: 700;
      font-size: 1.05rem;
      color: var(--text);
      letter-spacing: 0.05em;
    }
    .logo-badge {
      font-family: var(--font-body);
      font-size: 0.65rem;
      font-weight: 500;
      letter-spacing: 0.1em;
      color: var(--muted);
      background: var(--card);
      border: 1px solid var(--border);
      border-radius: 4px;
      padding: 1px 6px;
      margin-left: 2px;
    }
    .header-search {
      flex: 1;
      max-width: 480px;
      display: flex;
      align-items: center;
      gap: 0.5rem;
      background: var(--card);
      border: 1px solid var(--border);
      border-radius: var(--radius);
      padding: 0 0.875rem;
      height: 36px;
      cursor: pointer;
      transition: border-color var(--transition), box-shadow var(--transition);
    }
    .header-search:hover {
      border-color: var(--border-light);
      box-shadow: 0 0 0 2px rgba(212,160,23,0.08);
    }
    .search-icon { color: var(--muted); flex-shrink: 0; }
    .search-placeholder {
      flex: 1;
      color: var(--muted);
      font-size: 0.875rem;
      font-family: var(--font-body);
      user-select: none;
    }
    .search-kbd {
      display: flex;
      gap: 2px;
      flex-shrink: 0;
    }
    .search-kbd kbd {
      font-family: var(--font-body);
      font-size: 0.7rem;
      color: var(--muted);
      background: var(--surface);
      border: 1px solid var(--border-light);
      border-radius: 4px;
      padding: 1px 5px;
    }
    .header-right {
      margin-left: auto;
      display: flex;
      align-items: center;
      gap: 0.75rem;
    }
    .header-link {
      font-size: 0.85rem;
      color: var(--muted);
      font-weight: 500;
      transition: color var(--transition);
    }
    .header-link:hover { color: var(--text); }
    .header-cta {
      background: linear-gradient(135deg, var(--gold) 0%, #b8880e 100%);
      color: var(--bg);
      font-weight: 600;
      font-size: 0.8rem;
      padding: 0.4rem 1rem;
      border-radius: 6px;
      letter-spacing: 0.04em;
      transition: opacity var(--transition);
    }
    .header-cta:hover { opacity: 0.9; color: var(--bg); }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 4px;
      cursor: pointer;
      padding: 4px;
      background: none;
      border: none;
      flex-shrink: 0;
    }
    .hamburger span {
      display: block;
      width: 20px;
      height: 2px;
      background: var(--muted);
      border-radius: 2px;
      transition: all 0.25s;
    }
    .hamburger.open span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
    .hamburger.open span:nth-child(2) { opacity: 0; }
    .hamburger.open span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }
    /* ─────────────────────────────────────────────
       LAYOUT SHELL
    ───────────────────────────────────────────── */
    .layout {
      display: flex;
      margin-top: var(--header-h);
      min-height: calc(100vh - var(--header-h));
    }
    /* ─────────────────────────────────────────────
       SIDEBAR
    ───────────────────────────────────────────── */
    .sidebar {
      position: fixed;
      top: var(--header-h);
      left: 0;
      width: var(--sidebar-w);
      height: calc(100vh - var(--header-h));
      overflow-y: auto;
      padding: 1.5rem 0 3rem;
      border-right: 1px solid var(--border);
      background: var(--surface);
      z-index: 150;
      transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .sidebar-group { margin-bottom: 0.25rem; }
    .sidebar-close-btn { display: none; }
    .sidebar-group-label {
      font-family: var(--font-head);
      font-size: 0.65rem;
      font-weight: 700;
      letter-spacing: 0.12em;
      text-transform: uppercase;
      color: var(--muted);
      padding: 0.75rem 1.25rem 0.35rem;
      display: block;
    }
    .sidebar-item {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      padding: 0.45rem 1.25rem;
      font-size: 0.875rem;
      font-weight: 400;
      color: var(--muted-light);
      cursor: pointer;
      border-left: 2px solid transparent;
      transition: all var(--transition);
      user-select: none;
    }
    .sidebar-item:hover {
      color: var(--text);
      background: rgba(255,255,255,0.03);
    }
    .sidebar-item.active {
      color: var(--gold);
      border-left-color: var(--gold);
      background: var(--gold-dim);
      font-weight: 500;
    }
    .sidebar-item .dot {
      width: 5px;
      height: 5px;
      border-radius: 50%;
      background: currentColor;
      opacity: 0.5;
      flex-shrink: 0;
    }
    .sidebar-item.active .dot { opacity: 1; }
    /* Indented section links that scroll to an in-page anchor. */
    .sidebar-subitem {
      padding-top: 0.3rem;
      padding-bottom: 0.3rem;
      padding-left: 2.6rem;
      font-size: 0.8rem;
      color: var(--muted);
    }
    .sidebar-subitem .dot { width: 4px; height: 4px; opacity: 0.35; }
    .sidebar-overlay {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.6);
      z-index: 140;
      backdrop-filter: blur(2px);
    }
    .sidebar-overlay.visible {
      display: block;
    }
    /* ─────────────────────────────────────────────
       MAIN CONTENT
    ───────────────────────────────────────────── */
    .main {
      z-index: 1;
      margin-left: var(--sidebar-w);
      flex: 1;
      min-width: 0;
      display: flex;
    }
    .content-wrap {
      flex: 1;
      min-width: 0;
      padding: 3rem 3.5rem 6rem;
      max-width: 820px;
    }
    .right-nav-wrap {
      width: var(--right-w);
      flex-shrink: 0;
      position: sticky;
      top: calc(var(--header-h) + 1.5rem);
      align-self: flex-start;
      padding: 0 1rem;
      height: fit-content;
    }