:root {
      --primary: #5b4bdb;
      --primary-light: #ede9ff;
      --accent: #ff6b6b;
      --accent2: #ffa94d;
      --green: #20c997;
      --dark: #1a1a2e;
      --text: #2c2c54;
      --text-light: #6c6c8a;
      --bg: #f8f7ff;
      --card: #ffffff;
      --border: #e0dcf5;
      --shadow: 0 4px 24px rgba(91,75,219,0.10);
      --radius: 16px;
    }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
      background: var(--bg);
      color: var(--text);
      line-height: 1.8;
    }
    /* 轻量全局优化：观感更"松弛"但不稀疏 */
    a { text-underline-offset: 3px; }
    .section-header { scroll-margin-top: 84px; }
    .section[id],
    .toc#s0,
    #prompt,
    .card[id] {
      scroll-margin-top: 84px;
    }
    .card { transition: box-shadow .2s ease, transform .2s ease; }
    .card:has(.step-carousel):hover { box-shadow: 0 8px 28px rgba(91,75,219,0.12); }

    /* ===== SCROLLBAR ===== */
    html {
      scrollbar-gutter: stable;
    }
    * {
      scrollbar-width: thin;
      scrollbar-color: rgba(91, 75, 219, 0.55) rgba(224, 220, 245, 0.65);
    }
    *::-webkit-scrollbar {
      width: 10px;
      height: 10px;
    }
    *::-webkit-scrollbar-track {
      background: rgba(224, 220, 245, 0.55);
      border-radius: 100px;
    }
    *::-webkit-scrollbar-thumb {
      background: linear-gradient(180deg, rgba(139, 124, 255, 0.95) 0%, rgba(91, 75, 219, 0.88) 100%);
      border-radius: 100px;
      border: 2px solid rgba(248, 247, 255, 0.9);
      background-clip: padding-box;
      min-height: 36px;
    }
    *::-webkit-scrollbar-thumb:hover {
      background: linear-gradient(180deg, #9d91ff 0%, #6d5ae8 100%);
      border-color: rgba(248, 247, 255, 0.95);
    }
    *::-webkit-scrollbar-corner {
      background: transparent;
    }

    /* ===== 横向滑动步骤展示器 ===== */
    .step-carousel {
      position: relative;
      margin: 24px 0;
    }
    /* 轻微两侧渐隐，提示可横向滑动 */
    .step-carousel::before,
    .step-carousel::after {
      content: '';
      position: absolute;
      top: 0;
      bottom: 52px;
      width: 32px;
      pointer-events: none;
      z-index: 2;
      opacity: 0;
      transition: opacity .25s ease;
    }
    .step-carousel::before {
      left: 0;
      background: linear-gradient(90deg, rgba(248, 247, 255, 1), rgba(248, 247, 255, 0));
    }
    .step-carousel::after {
      right: 0;
      background: linear-gradient(270deg, rgba(248, 247, 255, 1), rgba(248, 247, 255, 0));
    }
    .step-carousel[data-can-scroll="true"]::before,
    .step-carousel[data-can-scroll="true"]::after {
      opacity: 1;
    }
    .step-carousel__track {
      display: flex;
      gap: 20px;
      overflow-x: auto;
      scroll-snap-type: x mandatory;
      scroll-behavior: smooth;
      padding: 8px 4px 16px;
      margin: 0 -4px;
      -webkit-overflow-scrolling: touch;
      scrollbar-width: none;
    }
    .step-carousel__track:focus-visible {
      outline: 3px solid rgba(91, 75, 219, 0.25);
      outline-offset: 6px;
      border-radius: 16px;
    }
    .step-carousel__track::-webkit-scrollbar {
      display: none;
    }
    .step-card {
      flex: 0 0 280px;
      scroll-snap-align: start;
      background: var(--card);
      border: 1.5px solid var(--border);
      border-radius: 18px;
      overflow: hidden;
      transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.3s ease;
      cursor: pointer;
    }
    .step-card:hover {
      transform: translateY(-4px);
      box-shadow: 0 12px 32px rgba(91, 75, 219, 0.15);
      border-color: var(--primary);
    }
    .step-card__num {
      display: flex;
      align-items: center;
      justify-content: center;
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--primary), #7c6fff);
      color: #fff;
      font-weight: 800;
      font-size: 15px;
      border-radius: 50%;
      margin: 16px 0 0 16px;
      box-shadow: 0 4px 12px rgba(91, 75, 219, 0.3);
    }
    .step-card__img {
      background: #1a1a2e;
      border-radius: 12px;
      margin: 12px 14px;
      overflow: hidden;
      aspect-ratio: 16/10;
    }
    .step-card__img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      display: block;
      transition: transform 0.4s ease;
    }
    .step-card:hover .step-card__img img {
      transform: scale(1.05);
    }
    .step-card__body {
      padding: 14px 16px 18px;
    }
    .step-card__title {
      font-size: 14px;
      font-weight: 700;
      color: var(--dark);
      margin-bottom: 6px;
    }
    .step-card__desc {
      font-size: 12px;
      color: var(--text-light);
      line-height: 1.6;
    }
    .step-card__tip {
      margin-top: 10px;
      padding: 8px 10px;
      background: var(--primary-light);
      border-radius: 8px;
      font-size: 11px;
      color: var(--primary);
      font-weight: 500;
    }
    /* 步骤连接线 */
    .step-connector {
      display: flex;
      align-items: center;
      justify-content: center;
      width: 32px;
      flex-shrink: 0;
      color: var(--border);
      font-size: 18px;
    }
    /* 轮播导航按钮 */
    .carousel-nav {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 16px;
      margin-top: 12px;
    }
    /* 胶囊式导航条：更"组件化"，更像成品 UI */
    .carousel-nav {
      width: fit-content;
      margin: 14px auto 0;
      padding: 8px 10px;
      border-radius: 999px;
      background: rgba(255, 255, 255, 0.72);
      border: 1px solid rgba(224, 220, 245, 0.95);
      box-shadow: 0 10px 28px rgba(91, 75, 219, 0.10);
      backdrop-filter: blur(10px);
      -webkit-backdrop-filter: blur(10px);
    }
    .carousel-btn {
      width: 44px;
      height: 44px;
      border-radius: 999px;
      border: 1.5px solid rgba(91, 75, 219, 0.35);
      background: linear-gradient(135deg, #ffffff, #f7f6ff);
      color: var(--primary);
      font-size: 20px;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s ease;
    }
    .carousel-btn:hover {
      background: linear-gradient(135deg, var(--primary), #7c6fff);
      color: #fff;
      transform: translateY(-1px);
      box-shadow: 0 10px 22px rgba(91, 75, 219, 0.22);
    }
    .carousel-btn:active {
      transform: translateY(0px);
      box-shadow: none;
    }
    .carousel-btn:focus-visible {
      outline: 3px solid rgba(91, 75, 219, 0.28);
      outline-offset: 3px;
    }
    .carousel-btn:disabled {
      opacity: 0.40;
      cursor: not-allowed;
      transform: none;
      box-shadow: none;
    }
    /* 进度指示器 */
    .carousel-dots {
      display: flex;
      gap: 8px;
      align-items: center;
    }
    .carousel-dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: rgba(224, 220, 245, 0.95);
      transition: all 0.3s ease;
      cursor: pointer;
    }
    .carousel-dot:hover { transform: scale(1.15); }
    .carousel-dot.active {
      background: linear-gradient(135deg, var(--primary), #7c6fff);
      width: 28px;
      border-radius: 6px;
    }

    /* 让轮播卡片在小屏更友好 */
    @media (max-width: 640px) {
      .step-card { flex-basis: 250px; }
      .carousel-btn { width: 40px; height: 40px; }
    }
    /* 横向流程概览 */
    .flow-overview {
      display: flex;
      align-items: center;
      gap: 8px;
      padding: 16px 20px;
      background: linear-gradient(135deg, var(--primary-light), #f0eeff);
      border-radius: 14px;
      margin-bottom: 20px;
      overflow-x: auto;
    }
    .flow-step {
      display: flex;
      align-items: center;
      gap: 6px;
      font-size: 13px;
      color: var(--primary);
      font-weight: 600;
      white-space: nowrap;
      flex-shrink: 0;
    }
    .flow-step__num {
      width: 22px;
      height: 22px;
      background: var(--primary);
      color: #fff;
      border-radius: 50%;
      font-size: 11px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .flow-arrow {
      color: var(--primary);
      opacity: 0.5;
      font-size: 16px;
      flex-shrink: 0;
    }

    /* ===== OFFICIAL DOC CARD ===== */
    .official-doc-card {
      background: linear-gradient(135deg, #f0eeff 0%, #e8e4ff 100%);
      border: 2px solid rgba(91, 75, 219, 0.25);
      border-radius: 16px;
      padding: 24px 28px;
      margin: 16px 0;
      position: relative;
      overflow: hidden;
    }
    .official-doc-card::before {
      content: '';
      position: absolute;
      top: 0; right: 0;
      width: 120px; height: 120px;
      background: radial-gradient(circle, rgba(91,75,219,0.12), transparent 70%);
      border-radius: 50%;
    }
    .official-doc-card .doc-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      background: var(--primary);
      color: #fff;
      font-size: 11px;
      font-weight: 700;
      padding: 3px 10px;
      border-radius: 20px;
      margin-bottom: 10px;
      letter-spacing: 0.5px;
    }
    .official-doc-card h4 {
      font-size: 17px;
      font-weight: 700;
      color: var(--dark);
      margin: 0 0 6px;
    }
    .official-doc-card p {
      font-size: 13px;
      color: var(--text-light);
      margin: 0 0 14px;
      line-height: 1.6;
    }
    /* ===== DOC HIGHLIGHT (must-read) ===== */
    .official-doc-card .doc-highlight {
      display: flex;
      gap: 10px;
      align-items: flex-start;
      padding: 12px 14px;
      margin: 10px 0 14px;
      border-radius: 12px;
      background: linear-gradient(135deg, rgba(255, 107, 107, 0.12), rgba(91, 75, 219, 0.10));
      border: 1.5px solid rgba(255, 107, 107, 0.35);
      color: #2b2b4a;
      box-shadow: 0 6px 18px rgba(255, 107, 107, 0.10);
      position: relative;
    }
    .official-doc-card .doc-highlight::before {
      content: '必读';
      display: inline-flex;
      align-items: center;
      justify-content: center;
      height: 18px;
      padding: 0 8px;
      border-radius: 999px;
      background: linear-gradient(135deg, var(--accent), #ff8a8a);
      color: #fff;
      font-size: 11px;
      font-weight: 800;
      letter-spacing: 0.5px;
      flex-shrink: 0;
      margin-top: 2px;
      box-shadow: 0 6px 16px rgba(255, 107, 107, 0.35);
    }
    .official-doc-card .doc-highlight strong {
      color: #1f1f3a;
      font-weight: 800;
    }
    .official-doc-card .doc-highlight code {
      background: rgba(91, 75, 219, 0.10);
      color: var(--primary);
      padding: 1px 6px;
      border-radius: 6px;
      font-family: 'Courier New', monospace;
      font-size: 12px;
    }
    .official-doc-card .doc-link {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      background: var(--primary);
      color: #fff;
      padding: 10px 22px;
      border-radius: 10px;
      text-decoration: none;
      font-size: 14px;
      font-weight: 600;
      box-shadow: 0 4px 14px rgba(91,75,219,0.35);
      transition: all 0.2s;
    }
    .official-doc-card .doc-link:hover {
      background: #4a3bc7;
      box-shadow: 0 6px 20px rgba(91,75,219,0.45);
      transform: translateY(-1px);
    }
    .doc-card-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
      margin-top: 16px;
    }

    /* ===== OFFICIAL ACCOUNT BADGE ===== */
    .official-badge {
      display: inline-flex;
      align-items: center;
      gap: 5px;
      background: linear-gradient(135deg, #ff4757, #ff6b81);
      color: #fff;
      font-size: 11px;
      font-weight: 700;
      padding: 3px 9px;
      border-radius: 20px;
      letter-spacing: 0.3px;
    }
    .account-card {
      background: #fff;
      border: 1.5px solid #f0e6ff;
      border-radius: 14px;
      padding: 20px 22px;
      display: flex;
      align-items: flex-start;
      gap: 14px;
      transition: all 0.2s;
      box-shadow: 0 2px 12px rgba(91,75,219,0.06);
    }
    .account-card:hover {
      border-color: rgba(91,75,219,0.3);
      box-shadow: 0 4px 20px rgba(91,75,219,0.12);
      transform: translateY(-2px);
    }
    .account-card .account-icon {
      width: 48px; height: 48px;
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 24px;
      flex-shrink: 0;
    }
    .account-card .account-info h4 {
      font-size: 15px;
      font-weight: 700;
      color: var(--dark);
      margin: 0 0 4px;
    }
    .account-card .account-info p {
      font-size: 12px;
      color: var(--text-light);
      margin: 0 0 10px;
      line-height: 1.5;
    }
    .account-card .account-link {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 6px 16px;
      border-radius: 8px;
      text-decoration: none;
      font-size: 13px;
      font-weight: 600;
      transition: all 0.2s;
    }
    .account-card .account-link:hover { opacity: 0.85; transform: translateY(-1px); }
    .account-xiaohongshu { background: #ff2442; color: #fff; }
    .account-douyin { background: #161823; color: #fff; border: 1px solid #333; }
    .account-bilibili { background: #00a1d6; color: #fff; }
    .account-zhihu { background: #0066ff; color: #fff; }
    .account-weixin { background: #07c160; color: #fff; }

    /* ===== HERO ===== */
    .hero {
      background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
      color: #fff;
      padding: 72px 40px 60px;
      text-align: center;
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      top: -80px; left: -80px;
      width: 320px; height: 320px;
      background: radial-gradient(circle, rgba(91,75,219,0.4), transparent 70%);
      border-radius: 50%;
    }
    .hero::after {
      content: '';
      position: absolute;
      bottom: -60px; right: -60px;
      width: 280px; height: 280px;
      background: radial-gradient(circle, rgba(255,107,107,0.3), transparent 70%);
      border-radius: 50%;
    }
    .hero-badge {
      display: inline-block;
      background: rgba(91,75,219,0.5);
      border: 1px solid rgba(91,75,219,0.8);
      border-radius: 20px;
      padding: 4px 16px;
      font-size: 13px;
      letter-spacing: 1px;
      margin-bottom: 20px;
      position: relative; z-index: 1;
    }
    .hero h1 {
      font-size: clamp(28px, 5vw, 52px);
      font-weight: 800;
      position: relative; z-index: 1;
      background: linear-gradient(90deg, #fff 0%, #c8b8ff 60%, #ff6b6b 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      line-height: 1.2;
      margin-bottom: 16px;
    }
    .hero p {
      font-size: 16px;
      color: rgba(255,255,255,0.75);
      max-width: 640px;
      margin: 0 auto 32px;
      position: relative; z-index: 1;
    }
    .hero-meta {
      display: flex;
      gap: 24px;
      justify-content: center;
      flex-wrap: wrap;
      position: relative; z-index: 1;
    }
    .hero-meta span {
      background: rgba(255,255,255,0.1);
      border: 1px solid rgba(255,255,255,0.2);
      border-radius: 8px;
      padding: 6px 16px;
      font-size: 13px;
      color: rgba(255,255,255,0.85);
    }

    /* ===== NAV ===== */
    .nav {
      background: var(--dark);
      padding: 0;
      position: sticky;
      top: 0;
      z-index: 100;
      border-bottom: 1px solid rgba(91,75,219,0.3);
      overflow-x: auto;
      white-space: nowrap;
    }
    .nav-inner {
      max-width: 1100px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .nav ul {
      list-style: none;
      display: flex;
      gap: 4px;
      padding: 0;
    }
    .nav a {
      display: block;
      padding: 14px 16px;
      color: rgba(255,255,255,0.6);
      text-decoration: none;
      font-size: 13px;
      transition: color .2s, background-color .2s;
      border-radius: 10px;
    }
    .nav a:hover { color: #fff; }
    .nav a.nav-link--active {
      color: #fff;
      background: rgba(124, 109, 255, 0.38);
      box-shadow: inset 0 0 0 1px rgba(255,255,255,0.12);
    }

    /* ===== CONTAINER ===== */
    .container {
      --container-pad: 24px;
      max-width: 1100px;
      margin: 0 auto;
      padding: 48px var(--container-pad);
    }

    /* ===== SECTION ===== */
    .section { margin-bottom: 64px; }
    .section-header {
      display: flex;
      align-items: center;
      gap: 14px;
      margin-bottom: 32px;
    }
    .section-icon {
      width: 48px; height: 48px;
      background: var(--primary-light);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 24px;
      flex-shrink: 0;
    }
    .section-title h2 {
      font-size: 24px;
      font-weight: 700;
      color: var(--dark);
    }
    .section-title p {
      font-size: 14px;
      color: var(--text-light);
      margin-top: 2px;
    }

    /* ===== CARD ===== */
    .card {
      background: var(--card);
      border-radius: var(--radius);
      border: 1px solid var(--border);
      box-shadow: var(--shadow);
      padding: 28px 32px;
      margin-bottom: 20px;
    }
    .card h3 {
      font-size: 17px;
      font-weight: 700;
      color: var(--dark);
      margin-bottom: 12px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .card h4 {
      font-size: 15px;
      font-weight: 600;
      color: var(--primary);
      margin: 18px 0 8px;
    }
    .card p { font-size: 14px; color: var(--text); line-height: 1.8; margin-bottom: 10px; }
    .card ul, .card ol { padding-left: 20px; }
    .card li { font-size: 14px; color: var(--text); line-height: 1.9; }

    /* ===== GRID ===== */
    .grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
    .grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
    @media(max-width: 768px) {
      .grid-2, .grid-3 { grid-template-columns: 1fr; }
      .hero { padding: 48px 20px 40px; }
      .container { --container-pad: 16px; padding: 32px var(--container-pad); }
      .nav-inner { padding: 0 16px; }
    }

    /* ===== TAG ===== */
    .tag {
      display: inline-block;
      padding: 3px 10px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 600;
      margin-right: 6px;
      margin-bottom: 4px;
    }
    .tag-purple { background: var(--primary-light); color: var(--primary); }
    .tag-red { background: #ffe5e5; color: #e03131; }
    .tag-green { background: #e6fcf5; color: #087f5b; }
    .tag-orange { background: #fff4e5; color: #d9480f; }
    .tag-blue { background: #e7f5ff; color: #1971c2; }

    /* ===== TABLE ===== */
    .table-wrap { overflow-x: auto; border-radius: 12px; border: 1px solid var(--border); margin: 16px 0; }
    table { width: 100%; border-collapse: collapse; font-size: 14px; }
    thead tr { background: var(--primary); color: #fff; }
    thead th { padding: 12px 16px; text-align: left; font-weight: 600; }
    tbody tr:nth-child(even) { background: var(--primary-light); }
    tbody td { padding: 11px 16px; border-bottom: 1px solid var(--border); vertical-align: top; }
    tbody tr:last-child td { border-bottom: none; }

    /* ===== CODE BLOCK ===== */
    .prompt-box {
      /* 提示词专用样式：强调紫色但保持可读 */
      background:
        linear-gradient(0deg, rgba(255,255,255,0.92), rgba(255,255,255,0.92)),
        radial-gradient(1200px 280px at 0% 0%, rgba(91,75,219,0.18) 0%, rgba(91,75,219,0.06) 55%, rgba(255,255,255,0) 100%);
      border-radius: 12px;
      padding: 20px 24px;
      margin: 14px 0;
      border-left: 6px solid var(--primary);
      border: 1.5px solid rgba(91, 75, 219, 0.30);
      box-shadow: 0 10px 28px rgba(91, 75, 219, 0.10);
      position: relative;
    }
    .prompt-box::before {
      content: '';
      position: absolute;
      left: 0;
      right: 0;
      top: 0;
      height: 3px;
      background: linear-gradient(90deg, rgba(91,75,219,0.85), rgba(124,109,255,0.65), rgba(255,255,255,0));
      border-top-left-radius: 12px;
      border-top-right-radius: 12px;
    }
    .prompt-box .label {
      font-size: 11px;
      color: #fff;
      letter-spacing: 1px;
      margin-bottom: 10px;
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 4px 10px;
      border-radius: 999px;
      background: linear-gradient(135deg, rgba(91,75,219,0.92), rgba(124,109,255,0.88));
      box-shadow: 0 6px 16px rgba(91,75,219,0.18);
    }
    .prompt-box p, .prompt-box li {
      font-size: 13px;
      color: #2c2c54;
      line-height: 1.8;
      font-family: 'Courier New', monospace;
    }
    .prompt-box ul { padding-left: 16px; }

    /* ===== STEP LIST ===== */
    .step-list { counter-reset: step; padding: 0; }
    .step-item {
      display: flex;
      gap: 16px;
      margin-bottom: 18px;
      align-items: flex-start;
    }
    .step-num {
      counter-increment: step;
      width: 32px; height: 32px;
      background: var(--primary);
      color: #fff;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 14px;
      flex-shrink: 0;
      margin-top: 2px;
    }
    .step-content h4 { font-size: 15px; font-weight: 600; color: var(--dark); margin-bottom: 4px; }
    .step-content p, .step-content li { font-size: 14px; color: var(--text); }

    /* 紧凑步骤卡片（如注册与登录）：与全局 step-list 一致，仅收紧间距 */
    .card.card--compact {
      padding: 20px 24px;
    }
    .card.card--compact > h3 {
      margin-bottom: 10px;
    }
    .step-list.step-list--compact .step-item {
      gap: 12px;
      margin-bottom: 10px;
    }
    .step-list.step-list--compact .step-item:last-child {
      margin-bottom: 0;
    }
    .step-list.step-list--compact .step-num {
      width: 28px;
      height: 28px;
      font-size: 13px;
      margin-top: 0;
    }
    .step-list.step-list--compact .step-content h4 {
      font-size: 14px;
      margin-bottom: 2px;
      line-height: 1.35;
    }
    .step-list.step-list--compact .step-content p {
      font-size: 13px;
      line-height: 1.6;
      margin-bottom: 0;
    }

    /* ===== HIGHLIGHT BOX ===== */
    .highlight {
      border-radius: 12px;
      padding: 18px 22px;
      margin: 16px 0;
      border-left: 4px solid;
    }
    .highlight-tip { background: #e6fcf5; border-color: var(--green); }
    .highlight-warn { background: #fff4e5; border-color: var(--accent2); }
    .highlight-danger { background: #ffe5e5; border-color: var(--accent); }
    .highlight strong { font-size: 13px; }
    .highlight p { font-size: 13px; color: var(--text); margin: 4px 0 0; }

    /* ===== FEATURE CARD ===== */
    .feature-card {
      background: var(--card);
      border-radius: var(--radius);
      border: 1px solid var(--border);
      padding: 24px;
      box-shadow: var(--shadow);
      transition: transform .2s, box-shadow .2s;
    }
    .feature-card:hover { transform: translateY(-2px); box-shadow: 0 8px 32px rgba(91,75,219,0.15); }
    .feature-card.feature-card--link { display: block; text-decoration: none; color: inherit; }
    .feature-card.feature-card--link:focus-visible {
      outline: 3px solid rgba(91, 75, 219, 0.25);
      outline-offset: 6px;
    }
    .feature-icon { font-size: 32px; margin-bottom: 12px; }
    .feature-card h3 { font-size: 16px; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
    .feature-card p { font-size: 13px; color: var(--text-light); line-height: 1.7; }

    /* ===== FORMULA ===== */
    .formula {
      background: linear-gradient(135deg, var(--primary-light), #fff0f5);
      border: 2px dashed var(--primary);
      border-radius: 12px;
      padding: 20px 24px;
      margin: 16px 0;
      text-align: center;
    }
    .formula .label { font-size: 12px; color: var(--text-light); margin-bottom: 8px; }
    .formula .content { font-size: 15px; font-weight: 700; color: var(--primary); }
    .formula .content span { color: var(--accent); }

    /* ===== CAMERA TABLE ===== */
    .cam-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px; margin: 16px 0; }
    .cam-item {
      background: var(--primary-light);
      border-radius: 10px;
      padding: 14px 16px;
    }
    .cam-item .en { font-size: 13px; font-weight: 700; color: var(--primary); }
    .cam-item .zh { font-size: 12px; color: var(--text-light); margin-top: 2px; }
    .cam-item .desc { font-size: 12px; color: var(--text); margin-top: 4px; }

    /* ===== DIVIDER ===== */
    hr { border: none; border-top: 1px solid var(--border); margin: 32px 0; }

    /* ===== TOC ===== */
    .toc {
      background: var(--card);
      border-radius: var(--radius);
      border: 1px solid var(--border);
      padding: 28px 32px;
      margin-bottom: 48px;
      /* 目录对齐 nav-inner（1100px）宽度 */
      width: calc(100% + (var(--container-pad) * 2));
      margin-left: calc(-1 * var(--container-pad));
      margin-right: calc(-1 * var(--container-pad));
    }
    .toc h2 { font-size: 18px; font-weight: 700; color: var(--dark); margin-bottom: 16px; }
    .toc-list { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 32px; }
    @media(max-width: 640px) { .toc-list { grid-template-columns: 1fr; } }
    .toc-item { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-size: 14px; padding: 6px 0; border-bottom: 1px dashed var(--border); }
    .toc-item:hover { color: var(--primary); }
    .toc-num { width: 24px; height: 24px; background: var(--primary); color: #fff; border-radius: 6px; font-size: 12px; font-weight: 700; display: flex; align-items: center; justify-content: center; flex-shrink: 0; }

    /* ===== FOOTER ===== */
    .footer {
      background: var(--dark);
      color: rgba(255,255,255,0.5);
      text-align: center;
      padding: 32px;
      font-size: 13px;
    }

    /* ===== PRINT ===== */
    @media print {
      .nav, .hero::before, .hero::after { display: none; }
    }

    /* ===== IMAGE PREVIEW (LIGHTBOX) ===== */
    .zoomable {
      cursor: zoom-in;
      user-select: none;
      -webkit-tap-highlight-color: transparent;
    }
    .zoomable:focus {
      outline: 3px solid rgba(91,75,219,0.35);
      outline-offset: 3px;
      border-radius: 10px;
    }
    .img-preview-backdrop {
      position: fixed;
      inset: 0;
      background: rgba(10, 12, 24, 0.72);
      display: none;
      align-items: center;
      justify-content: center;
      padding: 24px;
      z-index: 9999;
    }
    .img-preview-backdrop[data-open="true"] { display: flex; }
    .img-preview-dialog {
      position: relative;
      width: min(1100px, 100%);
      max-height: min(82vh, 900px);
      background: rgba(26, 26, 46, 0.30);
      border: 1px solid rgba(255,255,255,0.18);
      border-radius: 16px;
      box-shadow: 0 18px 60px rgba(0,0,0,0.45);
      overflow: hidden;
      backdrop-filter: blur(10px);
    }
    .img-preview-toolbar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      padding: 10px 12px;
      background: rgba(0,0,0,0.30);
      border-bottom: 1px solid rgba(255,255,255,0.12);
    }
    .img-preview-title {
      color: rgba(255,255,255,0.86);
      font-size: 13px;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
      padding-right: 8px;
    }
    .img-preview-close {
      appearance: none;
      border: 1px solid rgba(255,255,255,0.22);
      background: rgba(255,255,255,0.10);
      color: #fff;
      border-radius: 10px;
      padding: 8px 10px;
      font-weight: 700;
      cursor: pointer;
    }
    .img-preview-close:hover { background: rgba(255,255,255,0.16); }
    .img-preview-body {
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 12px;
      background: rgba(10,12,24,0.35);
      max-height: calc(82vh - 52px);
    }
    .img-preview-img {
      width: 100%;
      height: auto;
      max-height: calc(82vh - 76px);
      object-fit: contain;
      border-radius: 12px;
      background: rgba(255,255,255,0.06);
    }