:root {
      --bg-primary: #0d1117;
      --bg-secondary: #161b22;
      --bg-card: #1c2333;
      --bg-terminal: #0d1117;
      --text-primary: #e6edf3;
      --text-secondary: #8b949e;
      --accent: #58a6ff;
      --accent-hover: #79c0ff;
      --green: #3fb950;
      --orange: #d29922;
      --purple: #bc8cff;
      --red: #f85149;
      --border: #30363d;
      --shadow: rgba(0,0,0,0.4);
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, sans-serif;
      background: var(--bg-primary);
      color: var(--text-primary);
      line-height: 1.6;
    }

    /* Top nav */
    .topnav {
      background: var(--bg-secondary);
      border-bottom: 1px solid var(--border);
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 14px 24px;
      position: sticky;
      top: 0;
      z-index: 100;
    }
    .topnav .brand {
      font-weight: 700;
      font-size: 1.05rem;
      color: var(--text-primary);
      text-decoration: none;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .nav-links { display: flex; gap: 18px; }
    .nav-links a {
      color: var(--text-secondary);
      text-decoration: none;
      font-size: 0.92rem;
      padding: 6px 10px;
      border-radius: 6px;
      transition: all 0.2s;
    }
    .nav-links a:hover { color: var(--accent); }
    .nav-links a.active { color: var(--accent); background: rgba(88,166,255,0.12); }

    /* Page hero */
    .hero {
      text-align: center;
      padding: 80px 20px 60px;
      background: linear-gradient(135deg, #0d1117 0%, #161b22 50%, #1a2332 100%);
      border-bottom: 1px solid var(--border);
    }
    .hero h1 {
      font-size: 2.8rem;
      margin-bottom: 10px;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .hero p {
      color: var(--text-secondary);
      font-size: 1.15rem;
      max-width: 600px;
      margin: 0 auto 30px;
    }
    .hero .terminal-preview {
      background: var(--bg-terminal);
      border: 1px solid var(--border);
      border-radius: 8px;
      max-width: 550px;
      margin: 0 auto;
      text-align: left;
      overflow: hidden;
    }
    .terminal-bar {
      background: var(--bg-secondary);
      padding: 10px 14px;
      display: flex;
      align-items: center;
      gap: 8px;
      border-bottom: 1px solid var(--border);
    }
    .terminal-dot { width: 12px; height: 12px; border-radius: 50%; }
    .terminal-dot.red { background: var(--red); }
    .terminal-dot.yellow { background: var(--orange); }
    .terminal-dot.green { background: var(--green); }
    .terminal-body {
      padding: 20px;
      font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
      font-size: 0.95rem;
    }
    .terminal-body .line { margin-bottom: 4px; }
    .terminal-body .prompt { color: var(--green); }
    .terminal-body .cmd { color: var(--text-primary); }
    .terminal-body .output { color: var(--text-secondary); }

    .page-hero {
      text-align: center;
      padding: 55px 20px 40px;
      border-bottom: 1px solid var(--border);
      background: linear-gradient(135deg, #0d1117 0%, #161b22 50%, #1a2332 100%);
    }
    .page-hero h1 {
      font-size: 2.2rem;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .page-hero p {
      color: var(--text-secondary);
      max-width: 640px;
      margin: 10px auto 0;
      font-size: 1.05rem;
    }

    /* Home page cards */
    .page-cards {
      max-width: 1000px;
      margin: 50px auto 0;
      padding: 0 20px;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 20px;
    }
    .page-card {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 26px;
      text-decoration: none;
      color: var(--text-primary);
      transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
    }
    .page-card:hover {
      transform: translateY(-3px);
      border-color: var(--accent);
      box-shadow: 0 8px 30px var(--shadow);
    }
    .page-card h3 { color: var(--accent); margin-bottom: 8px; }
    .page-card p { color: var(--text-secondary); font-size: 0.9rem; }
    .page-card .tag {
      display: inline-block;
      margin-top: 12px;
      font-size: 0.8rem;
      font-weight: 600;
      color: var(--purple);
    }

    /* Search & Filter */
    .controls {
      max-width: 900px;
      margin: 25px auto 0;
      padding: 0 20px;
    }
    .search-box {
      width: 100%;
      padding: 16px 20px 16px 50px;
      border: 1px solid var(--border);
      border-radius: 10px;
      background: var(--bg-card);
      color: var(--text-primary);
      font-size: 1rem;
      outline: none;
      transition: border 0.2s;
    }
    .search-box:focus { border-color: var(--accent); }
    .search-wrapper {
      position: relative;
    }
    .search-icon {
      position: absolute;
      left: 18px;
      top: 50%;
      transform: translateY(-50%);
      color: var(--text-secondary);
      font-size: 1.1rem;
    }

    /* Stats */
    .stats {
      display: flex;
      justify-content: center;
      gap: 40px;
      margin-top: 25px;
      flex-wrap: wrap;
    }
    .stat {
      text-align: center;
    }
    .stat-num {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--accent);
    }
    .stat-label {
      color: var(--text-secondary);
      font-size: 0.85rem;
    }

    /* Category Tabs */
    .tabs {
      display: flex;
      justify-content: center;
      flex-wrap: wrap;
      gap: 10px;
      margin: 40px 20px 10px;
      max-width: 900px;
      margin-left: auto;
      margin-right: auto;
    }
    .tab {
      padding: 8px 18px;
      border-radius: 20px;
      border: 1px solid var(--border);
      background: transparent;
      color: var(--text-secondary);
      cursor: pointer;
      font-size: 0.9rem;
      transition: all 0.2s;
    }
    .tab:hover { border-color: var(--accent); color: var(--accent); }
    .tab.active {
      background: var(--accent);
      color: #fff;
      border-color: var(--accent);
    }

    /* Commands Grid */
    .commands-grid {
      max-width: 1200px;
      margin: 30px auto;
      padding: 0 20px;
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
      gap: 20px;
    }

    .command-card {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 24px;
      transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
      opacity: 0;
      transform: translateY(20px);
      animation: fadeIn 0.4s forwards;
    }
    .command-card:hover {
      transform: translateY(-3px);
      border-color: var(--accent);
      box-shadow: 0 8px 30px var(--shadow);
    }
    @keyframes fadeIn {
      to { opacity: 1; transform: translateY(0); }
    }

    .card-header {
      display: flex;
      align-items: center;
      gap: 10px;
      margin-bottom: 10px;
    }
    .cmd-name {
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 1.15rem;
      font-weight: 600;
      color: var(--accent);
    }
    .cmd-badge {
      font-size: 0.7rem;
      padding: 2px 8px;
      border-radius: 10px;
      font-weight: 600;
      text-transform: uppercase;
    }
    .badge-essential { background: rgba(63,185,80,0.15); color: var(--green); }
    .badge-common { background: rgba(88,166,255,0.15); color: var(--accent); }
    .badge-advanced { background: rgba(210,153,34,0.15); color: var(--orange); }

    .cmd-desc {
      color: var(--text-secondary);
      font-size: 0.92rem;
      margin-bottom: 14px;
    }

    .cmd-usage {
      color: var(--purple);
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.82rem;
      margin-bottom: 10px;
      padding: 2px 0;
    }

    .cmd-options {
      margin-bottom: 12px;
    }
    .cmd-options .label {
      font-size: 0.7rem;
      color: var(--text-secondary);
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-bottom: 6px;
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    }
    .options-list {
      display: flex;
      flex-direction: column;
      gap: 4px;
      max-height: 180px;
      overflow-y: auto;
      padding-right: 4px;
    }
    .options-list::-webkit-scrollbar { width: 4px; }
    .options-list::-webkit-scrollbar-track { background: transparent; }
    .options-list::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
    .option-item {
      display: flex;
      gap: 10px;
      align-items: baseline;
      font-size: 0.82rem;
      line-height: 1.4;
    }
    .option-flag {
      color: var(--green);
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.78rem;
      white-space: nowrap;
      flex-shrink: 0;
    }
    .option-desc {
      color: var(--text-secondary);
      font-size: 0.8rem;
    }

    .cmd-example {
      background: var(--bg-terminal);
      border: 1px solid var(--border);
      border-radius: 8px;
      padding: 14px;
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.85rem;
      overflow-x: auto;
    }
    .cmd-example .label {
      font-size: 0.7rem;
      color: var(--text-secondary);
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-bottom: 6px;
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    }
    .cmd-example .cmd-line {
      color: var(--green);
      margin-bottom: 4px;
    }
    .cmd-example .cmd-line::before {
      content: '$ ';
      color: var(--text-secondary);
    }
    .cmd-example .cmd-output {
      color: var(--text-secondary);
      white-space: pre;
    }

    .no-results {
      text-align: center;
      padding: 60px 20px;
      color: var(--text-secondary);
      font-size: 1.1rem;
      grid-column: 1 / -1;
    }
    .no-results .icon { font-size: 3rem; margin-bottom: 10px; }

    /* Footer */
    footer {
      text-align: center;
      padding: 40px 20px;
      color: var(--text-secondary);
      font-size: 0.85rem;
      border-top: 1px solid var(--border);
      margin-top: 40px;
    }
    footer a { color: var(--accent); text-decoration: none; }

    /* Responsive */
    @media (max-width: 600px) {
      .hero h1 { font-size: 1.8rem; }
      .hero p { font-size: 1rem; }
      .commands-grid { grid-template-columns: 1fr; }
      .stats { gap: 20px; }
      .topnav { flex-direction: column; gap: 10px; }
      .nav-links { gap: 8px; }
    }

    /* ── Live Terminal ── */
    .terminal-section {
      max-width: 900px;
      margin: 50px auto 0;
      padding: 0 20px;
    }
    .terminal-section h2 {
      font-size: 1.6rem;
      margin-bottom: 6px;
    }
    .terminal-section .subtitle {
      color: var(--text-secondary);
      font-size: 0.95rem;
      margin-bottom: 18px;
    }
    .terminal-section .subtitle code {
      background: var(--bg-card);
      color: var(--green);
      padding: 1px 6px;
      border-radius: 4px;
      font-family: 'SF Mono', 'Fira Code', monospace;
    }
    .term-window {
      background: var(--bg-terminal);
      border: 1px solid var(--border);
      border-radius: 12px;
      overflow: hidden;
      box-shadow: 0 12px 40px var(--shadow);
    }
    .term-title {
      margin-left: 10px;
      color: var(--text-secondary);
      font-size: 0.8rem;
    }
    .term-body {
      height: 300px;
      overflow-y: auto;
      padding: 16px 18px;
      font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
      font-size: 0.9rem;
      line-height: 1.55;
    }
    .term-line {
      white-space: pre-wrap;
      word-break: break-word;
      margin-bottom: 6px;
    }
    .term-prompt { color: var(--green); }
    .term-cmd { color: var(--text-primary); }
    .term-out { color: var(--text-secondary); }
    .term-err { color: var(--red); }
    .term-note { color: var(--orange); font-style: italic; }
    .term-input-line {
      display: flex;
      align-items: center;
      gap: 8px;
      padding: 10px 18px;
      border-top: 1px solid var(--border);
      background: var(--bg-secondary);
    }
    #term-input {
      flex: 1;
      background: transparent;
      border: none;
      outline: none;
      color: var(--text-primary);
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.9rem;
    }
    .term-actions {
      display: flex;
      align-items: center;
      gap: 8px;
      padding: 8px 18px;
      border-top: 1px solid var(--border);
      background: var(--bg-secondary);
    }
    .term-btn {
      background: var(--bg-card);
      color: var(--text-secondary);
      border: 1px solid var(--border);
      border-radius: 6px;
      padding: 5px 12px;
      font-size: 0.8rem;
      cursor: pointer;
      transition: all 0.2s;
    }
    .term-btn:hover { color: var(--accent); border-color: var(--accent); }
    .term-btn:disabled { opacity: 0.4; cursor: default; }
    .term-hint {
      margin-left: auto;
      color: var(--text-secondary);
      font-size: 0.75rem;
    }
    .btn-run {
      margin-top: 14px;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      background: rgba(63,185,80,0.12);
      color: var(--green);
      border: 1px solid rgba(63,185,80,0.35);
      border-radius: 6px;
      padding: 6px 12px;
      font-size: 0.8rem;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s;
    }
    .btn-run:hover { background: rgba(63,185,80,0.25); }
    .btn-run:active { transform: translateY(1px); }
    @media (max-width: 600px) {
      .term-body { height: 220px; }
    }

    /* Hero buttons */
    .hero-btns {
      display: flex;
      justify-content: center;
      gap: 12px;
      flex-wrap: wrap;
      margin-bottom: 30px;
    }
    .hero-btn {
      display: inline-block;
      padding: 11px 26px;
      border-radius: 8px;
      font-size: 0.95rem;
      font-weight: 600;
      text-decoration: none;
      cursor: pointer;
      border: 1px solid var(--border);
      background: var(--bg-card);
      color: var(--text-primary);
      transition: all 0.2s;
    }
    .hero-btn.primary {
      background: linear-gradient(135deg, var(--accent), var(--purple));
      color: #fff;
      border: none;
    }
    .hero-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 30px var(--shadow); }

    /* ── Quiz Section ── */
    .quiz-section {
      max-width: 900px;
      margin: 40px auto 0;
      padding: 0 20px;
    }
    .quiz-section h2 {
      font-size: 1.6rem;
      margin-bottom: 6px;
    }
    .quiz-subtitle {
      color: var(--text-secondary);
      font-size: 0.95rem;
      margin-bottom: 20px;
    }
    .quiz-card {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 12px;
      padding: 28px;
    }
    .quiz-progress {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 18px;
      font-size: 0.85rem;
      color: var(--text-secondary);
    }
    .quiz-progress-bar {
      height: 8px;
      background: var(--bg-secondary);
      border-radius: 4px;
      overflow: hidden;
      margin-bottom: 24px;
    }
    .quiz-progress-fill {
      height: 100%;
      width: 0%;
      background: linear-gradient(90deg, var(--accent), var(--purple));
      transition: width 0.3s;
    }
    .quiz-question {
      font-size: 1.15rem;
      margin-bottom: 20px;
      line-height: 1.5;
    }
    .quiz-question code, .quiz-option code {
      background: var(--bg-terminal);
      color: var(--green);
      padding: 1px 6px;
      border-radius: 4px;
      font-family: 'SF Mono', 'Fira Code', monospace;
    }
    .quiz-options {
      display: flex;
      flex-direction: column;
      gap: 12px;
    }
    .quiz-option {
      text-align: left;
      background: var(--bg-secondary);
      border: 1px solid var(--border);
      color: var(--text-primary);
      border-radius: 8px;
      padding: 14px 16px;
      font-size: 0.95rem;
      cursor: pointer;
      transition: all 0.2s;
      font-family: inherit;
    }
    .quiz-option:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
    .quiz-option:disabled { cursor: default; opacity: 0.7; }
    .quiz-option.correct {
      border-color: var(--green);
      background: rgba(63,185,80,0.15);
      color: var(--green);
    }
    .quiz-option.wrong {
      border-color: var(--red);
      background: rgba(248,81,73,0.15);
      color: var(--red);
    }
    .quiz-option.dim { opacity: 0.45; }
    .quiz-option .opt-letter {
      font-weight: 700;
      margin-right: 8px;
      color: var(--text-secondary);
    }
    .quiz-feedback {
      margin-top: 16px;
      padding: 14px 16px;
      border-radius: 8px;
      font-size: 0.9rem;
      display: none;
    }
    .quiz-feedback.show { display: block; }
    .quiz-feedback.good { background: rgba(63,185,80,0.1); border: 1px solid rgba(63,185,80,0.35); color: var(--green); }
    .quiz-feedback.bad { background: rgba(248,81,73,0.1); border: 1px solid rgba(248,81,73,0.35); color: var(--red); }
    .quiz-next {
      margin-top: 20px;
      background: var(--accent);
      color: #fff;
      border: none;
      border-radius: 8px;
      padding: 12px 24px;
      font-size: 0.95rem;
      font-weight: 600;
      cursor: pointer;
      display: none;
      transition: all 0.2s;
    }
    .quiz-next:hover { background: var(--accent-hover); }
    .quiz-result {
      text-align: center;
      padding: 20px 0;
    }
    .quiz-result .score-big {
      font-size: 3rem;
      font-weight: 800;
      color: var(--accent);
    }
    .quiz-result .score-sub { color: var(--text-secondary); margin-bottom: 16px; }
    .quiz-result .grade { font-size: 1.3rem; font-weight: 700; margin-bottom: 6px; }
    .quiz-review {
      margin-top: 24px;
      text-align: left;
    }
    .quiz-review h4 { margin-bottom: 12px; color: var(--text-primary); }
    .review-item {
      background: var(--bg-secondary);
      border: 1px solid var(--border);
      border-left: 3px solid var(--red);
      border-radius: 6px;
      padding: 12px 14px;
      margin-bottom: 10px;
      font-size: 0.88rem;
    }
    .review-item code { color: var(--green); font-family: 'SF Mono', 'Fira Code', monospace; }
    .review-item .rev-q { color: var(--text-primary); margin-bottom: 4px; }
    .review-item .rev-your { color: var(--red); }
    .review-item .rev-correct { color: var(--green); }
    .quiz-cat-row {
      display: flex;
      justify-content: space-between;
      gap: 10px;
      padding: 8px 2px;
      border-bottom: 1px dashed var(--border);
      font-size: 0.85rem;
      color: var(--text-secondary);
    }
    .quiz-cat-row span:last-child { color: var(--accent); font-weight: 600; }
    .btn-quiz-start {
      margin-top: 6px;
      background: linear-gradient(135deg, var(--accent), var(--purple));
      color: #fff;
      border: none;
      border-radius: 8px;
      padding: 14px 32px;
      font-size: 1rem;
      font-weight: 700;
      cursor: pointer;
      transition: transform 0.2s, box-shadow 0.2s;
    }
    .btn-quiz-start:hover { transform: translateY(-2px); box-shadow: 0 8px 30px var(--shadow); }
    .quiz-intro-stats {
      display: flex;
      justify-content: center;
      gap: 30px;
      margin: 20px 0;
      flex-wrap: wrap;
    }

    /* Quiz mode tabs */
    .quiz-mode-tabs {
      display: flex;
      justify-content: center;
      gap: 12px;
      margin: 40px 20px 0;
      flex-wrap: wrap;
    }
    .quiz-mode-tab {
      padding: 10px 22px;
      border-radius: 20px;
      border: 1px solid var(--border);
      background: transparent;
      color: var(--text-secondary);
      cursor: pointer;
      font-size: 0.95rem;
      font-weight: 600;
      transition: all 0.2s;
    }
    .quiz-mode-tab:hover { border-color: var(--purple); color: var(--purple); }
    .quiz-mode-tab.active { background: var(--purple); border-color: var(--purple); color: #fff; }

    /* ── Hands-on exercises ── */
    .practice-task {
      font-size: 1.1rem;
      margin-bottom: 14px;
      line-height: 1.5;
    }
    .practice-task code {
      background: var(--bg-terminal);
      color: var(--green);
      padding: 1px 6px;
      border-radius: 4px;
      font-family: 'SF Mono', 'Fira Code', monospace;
    }
    .practice-files {
      font-size: 0.82rem;
      color: var(--text-secondary);
      margin-bottom: 12px;
    }
    .practice-files code {
      background: var(--bg-card);
      color: var(--orange);
      padding: 1px 5px;
      border-radius: 4px;
      font-family: 'SF Mono', 'Fira Code', monospace;
    }
    .practice-terminal {
      background: var(--bg-terminal);
      border: 1px solid var(--border);
      border-radius: 10px;
      overflow: hidden;
    }
    .practice-term-body {
      height: 170px;
      overflow-y: auto;
      padding: 12px 14px;
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.85rem;
      line-height: 1.5;
    }
    .practice-input-line {
      display: flex;
      align-items: center;
      gap: 8px;
      padding: 10px 14px;
      border-top: 1px solid var(--border);
      background: var(--bg-secondary);
    }
    .practice-input {
      flex: 1;
      background: transparent;
      border: none;
      outline: none;
      color: var(--text-primary);
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.85rem;
    }
    .practice-actions {
      display: flex;
      gap: 10px;
      margin-top: 14px;
      flex-wrap: wrap;
    }
    .btn-check {
      background: var(--accent);
      color: #fff;
      border: none;
      border-radius: 8px;
      padding: 10px 22px;
      font-size: 0.9rem;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s;
    }
    .btn-check:hover { background: var(--accent-hover); }
    .btn-hint {
      background: transparent;
      color: var(--orange);
      border: 1px solid rgba(210,153,34,0.4);
      border-radius: 8px;
      padding: 10px 22px;
      font-size: 0.9rem;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s;
    }
    .btn-hint:hover { background: rgba(210,153,34,0.12); }
    .practice-hint {
      margin-top: 12px;
      padding: 12px 14px;
      border-radius: 8px;
      background: rgba(210,153,34,0.1);
      border: 1px solid rgba(210,153,34,0.35);
      color: var(--orange);
      font-size: 0.88rem;
      display: none;
    }
    .practice-hint.show { display: block; }
    .practice-hint code {
      color: var(--green);
      font-family: 'SF Mono', 'Fira Code', monospace;
    }
    .btn-check:disabled { opacity: 0.5; cursor: default; }

    /* ── Playground: command reference panel ── */
    .term-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 18px;
    }
    .term-header h2 { margin-bottom: 6px; }
    .term-header .subtitle { margin-bottom: 0; }
    .ref-toggle { font-weight: 600; }
    .ref-toggle-on {
      color: var(--purple);
      border-color: var(--purple);
    }
    .split-layout {
      display: flex;
      gap: 16px;
      align-items: flex-start;
    }
    .split-layout .term-window { flex: 1; min-width: 0; }
    .ref-panel {
      flex: 0 0 340px;
      max-width: 340px;
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: 12px;
      overflow: hidden;
      display: flex;
      flex-direction: column;
      max-height: 480px;
    }
    .ref-search-wrap {
      position: relative;
      padding: 12px;
      border-bottom: 1px solid var(--border);
      background: var(--bg-secondary);
    }
    .ref-search {
      width: 100%;
      padding: 10px 12px;
      padding-right: 76px;
      border: 1px solid var(--border);
      border-radius: 8px;
      background: var(--bg-card);
      color: var(--text-primary);
      font-size: 0.9rem;
      outline: none;
      transition: border 0.2s;
    }
    .ref-search:focus { border-color: var(--accent); }
    .ref-count {
      position: absolute;
      right: 24px;
      top: 50%;
      transform: translateY(-50%);
      color: var(--text-secondary);
      font-size: 0.72rem;
      pointer-events: none;
    }
    .ref-list {
      overflow-y: auto;
      flex: 1;
    }
    .ref-group-title {
      position: sticky;
      top: 0;
      z-index: 1;
      background: var(--bg-card);
      padding: 8px 14px;
      font-size: 0.72rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: var(--purple);
      border-bottom: 1px solid var(--border);
    }
    .ref-item {
      display: flex;
      align-items: center;
      gap: 10px;
      padding: 8px 14px;
      cursor: pointer;
      border-bottom: 1px solid rgba(48,54,61,0.5);
      transition: background 0.15s;
    }
    .ref-item:hover { background: rgba(88,166,255,0.08); }
    .ref-item-name {
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--accent);
      flex-shrink: 0;
      min-width: 96px;
    }
    .ref-item-usage {
      color: var(--text-secondary);
      font-family: 'SF Mono', 'Fira Code', monospace;
      font-size: 0.72rem;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
    }
    .ref-item-run {
      margin-left: auto;
      flex-shrink: 0;
      background: rgba(63,185,80,0.12);
      color: var(--green);
      border: 1px solid rgba(63,185,80,0.35);
      border-radius: 5px;
      padding: 2px 9px;
      font-size: 0.72rem;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.15s;
    }
    .ref-item-run:hover { background: rgba(63,185,80,0.25); }
    @media (max-width: 760px) {
      .split-layout { flex-direction: column; }
      .ref-panel { flex: none; width: 100%; max-width: none; max-height: 260px; }
    }