/* ── Design tokens ── */
    :root {
      --bg: #f0f2f5;
      --surface: #ffffff;
      --surface-hover: #f8f9fa;
      --border: #e0e3e8;
      --text: #1a1d23;
      --muted: #6b7280;
      --primary: #2563eb;
      --primary-hover: #1d4ed8;
      --primary-subtle: #eff6ff;
      --success: #16a34a;
      --warning-text: #92400e;
      --warning-bg: #fef3c7;
      --radius-sm: 6px;
      --radius: 10px;
      --radius-lg: 14px;
      --shadow: 0 1px 4px rgba(0, 0, 0, 0.08), 0 4px 16px rgba(0, 0, 0, 0.06);
      --transition: 0.15s ease;
    }

    /* ── Reset ── */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
      min-height: 100vh;
    }

    button,
    input,
    textarea {
      font: inherit;
    }

    /* ── Header ── */
    header {
      background: var(--surface);
      border-bottom: 1px solid var(--border);
      padding: 0 2rem;
      height: 56px;
      display: flex;
      align-items: center;
      position: sticky;
      top: 0;
      z-index: 200;
      box-shadow: 0 1px 0 var(--border);
    }

    header h1 {
      font-size: 1.125rem;
      font-weight: 700;
      letter-spacing: -0.01em;
    }

    header h1 span {
      font-weight: 400;
      color: var(--muted);
      margin-left: 0.5rem;
      font-size: 0.875rem;
    }

    /* ── Layout ── */
    main {
      display: grid;
      grid-template-columns: 280px 1fr;
      gap: 1.5rem;
      max-width: 1140px;
      margin: 0 auto;
      padding: 1.5rem;
      align-items: start;
      min-height: calc(100vh - 56px);
    }

    /* ── Panel base ── */
    .panel {
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow);
      overflow: hidden;
    }

    /* ── List panel ── */
    .panel-header {
      padding: 0.875rem 1rem 0.75rem;
      border-bottom: 1px solid var(--border);
      font-size: 0.6875rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--muted);
    }

    .bookmarklet-list {
      list-style: none;
    }

    .bookmarklet-item {
      display: flex;
      align-items: center;
      padding: 0.625rem 0.75rem 0.625rem 1rem;
      border-bottom: 1px solid var(--border);
      gap: 0.375rem;
      transition: background var(--transition), box-shadow var(--transition);
    }

    .bookmarklet-item:last-child { border-bottom: none; }

    .bookmarklet-item:hover { background: var(--surface-hover); }

    .bookmarklet-item.selected {
      background: var(--primary-subtle);
      box-shadow: inset 3px 0 0 var(--primary);
    }

    .bookmarklet-item.selected .item-name {
      color: var(--primary);
      font-weight: 600;
    }

    .item-name {
      flex: 1;
      cursor: pointer;
      font-size: 0.9375rem;
      font-weight: 500;
      padding: 0.5rem 0.625rem;
      min-width: 0;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
      border-radius: var(--radius-sm);
      transition: color var(--transition), background var(--transition), transform var(--transition);
      appearance: none;
      background: transparent;
      border: 0;
      color: inherit;
      text-align: left;
      box-shadow: none;
    }

    .item-name:hover {
      color: var(--primary);
      background: rgba(37, 99, 235, 0.08);
    }

    /* ── Icon buttons ── */
    .icon-btn {
      flex-shrink: 0;
      display: flex;
      align-items: center;
      justify-content: center;
      width: 32px;
      height: 32px;
      background: transparent;
      border: 0;
      border-radius: 999px;
      cursor: pointer;
      color: var(--muted);
      transition: color var(--transition), background var(--transition), transform var(--transition);
      font-size: 0.9rem;
      appearance: none;
      box-shadow: none;
    }

    .icon-btn:hover {
      background: rgba(15, 23, 42, 0.08);
      color: var(--text);
    }

    .icon-btn:active { transform: scale(0.92); }

    .icon-btn.copied { color: var(--success) !important; background: rgba(22, 163, 74, 0.12); }

    /* ── Loading / empty ── */
    .state-box {
      padding: 2.5rem 1.5rem;
      text-align: center;
      color: var(--muted);
      font-size: 0.9rem;
    }

    .spinner {
      display: inline-block;
      width: 22px;
      height: 22px;
      border: 2px solid var(--border);
      border-top-color: var(--primary);
      border-radius: 50%;
      animation: spin 0.7s linear infinite;
      margin-bottom: 0.625rem;
    }

    @keyframes spin { to { transform: rotate(360deg); } }

    /* ── Detail panel ── */
    #detail-panel {
      display: none;
    }

    #detail-panel.visible {
      display: flex;
      flex-direction: column;
      min-height: clamp(28rem, calc(100vh - 7rem), 64rem);
      max-height: calc(100vh - 7rem);
    }

    .detail-head {
      padding: 1.25rem 1.5rem;
      border-bottom: 1px solid var(--border);
    }

    .detail-title-row {
      display: flex;
      align-items: flex-start;
      gap: 1rem;
      flex-wrap: wrap;
    }

    .detail-title {
      flex: 1;
      font-size: 1.375rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      min-width: 0;
    }

    .detail-actions {
      display: flex;
      gap: 0.5rem;
      flex-shrink: 0;
      flex-wrap: wrap;
    }

    /* ── Buttons ── */
    .btn {
      display: inline-flex;
      align-items: center;
      gap: 0.375rem;
      padding: 0.4375rem 0.875rem;
      border-radius: var(--radius-sm);
      border: 1px solid var(--border);
      background: var(--surface);
      color: var(--text);
      cursor: pointer;
      font-size: 0.8125rem;
      font-weight: 500;
      text-decoration: none;
      transition: all var(--transition);
      white-space: nowrap;
    }

    .btn:hover { background: var(--surface-hover); border-color: #c0c5cc; }
    .btn:active { transform: scale(0.97); }

    .btn-primary {
      background: var(--primary);
      color: #fff;
      border-color: var(--primary);
    }

    .btn-primary:hover {
      background: var(--primary-hover);
      border-color: var(--primary-hover);
    }

    .btn svg, .btn-icon { flex-shrink: 0; }

    /* ── Info section ── */
    .detail-info {
      flex: 1 1 auto;
      padding: 1.25rem 1.5rem;
      border-bottom: 1px solid var(--border);
      overflow-y: auto;
      min-height: 0;
    }

    /* ── Markdown rendering ── */
    .detail-info h1 { font-size: 1.35rem; margin-bottom: 0.75rem; letter-spacing: -0.01em; }
    .detail-info h2 { font-size: 1.1rem; margin: 1.1rem 0 0.5rem; letter-spacing: -0.01em; }
    .detail-info h3 { font-size: 0.975rem; margin: 0.875rem 0 0.375rem; }
    .detail-info p  { margin-bottom: 0.75rem; font-size: 0.9375rem; color: #374151; }
    .detail-info ul, .detail-info ol { margin: 0.375rem 0 0.75rem 1.5rem; font-size: 0.9375rem; color: #374151; }
    .detail-info li { margin-bottom: 0.25rem; }
    .detail-info code {
      font-family: "SFMono-Regular", Consolas, monospace;
      font-size: 0.8125rem;
      background: #f1f3f5;
      padding: 0.1em 0.4em;
      border-radius: 4px;
    }
    .detail-info pre {
      background: #1e1e2e;
      color: #cdd6f4;
      padding: 1rem;
      border-radius: var(--radius-sm);
      overflow-x: auto;
      margin-bottom: 0.75rem;
    }
    .detail-info pre code { background: none; padding: 0; color: inherit; font-size: 0.8125rem; }
    .detail-info a { color: var(--primary); }
    .detail-info strong { font-weight: 600; }

    /* ── Code section ── */
    .detail-code {
      flex: 0 0 auto;
      padding: 1.25rem 1.5rem;
    }

    .code-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 0.75rem;
      margin-bottom: 0.5rem;
    }

    .code-label {
      display: block;
      font-size: 0.6875rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--muted);
    }

    .code-textarea {
      width: 100%;
      min-height: clamp(12rem, 28vh, 22rem);
      font-family: "SFMono-Regular", Consolas, "Courier New", monospace;
      font-size: 0.8125rem;
      line-height: 1.6;
      padding: 0.875rem 1rem;
      border: 1px solid var(--border);
      border-radius: var(--radius-sm);
      background: #1e1e2e;
      color: #cdd6f4;
      resize: vertical;
      outline: none;
      tab-size: 2;
    }

    .code-textarea:focus { border-color: var(--primary); }

    /* ── Toast ── */
    .toast {
      position: fixed;
      bottom: 1.75rem;
      left: 50%;
      transform: translateX(-50%) translateY(1rem);
      background: #111827;
      color: #f9fafb;
      padding: 0.625rem 1.375rem;
      border-radius: 999px;
      font-size: 0.875rem;
      font-weight: 500;
      opacity: 0;
      transition: opacity 0.25s, transform 0.25s;
      pointer-events: none;
      z-index: 500;
      white-space: nowrap;
    }

    .toast.show {
      opacity: 1;
      transform: translateX(-50%) translateY(0);
    }

    /* ── Favorite modal ── */

    /* ── Responsive ── */
    @media (max-width: 720px) {
      main {
        grid-template-columns: 1fr;
        padding: 1rem;
        gap: 1rem;
        min-height: auto;
      }

      #detail-panel.visible {
        min-height: 0;
        max-height: none;
      }

      .detail-title-row { flex-direction: column; }
      .detail-actions { width: 100%; }
    }

    /* ── Focus styles ── */
    :focus-visible {
      outline: 2px solid var(--primary);
      outline-offset: 2px;
    }