:root {
      --primary: #1e40af;
      --primary-hover: #1d4ed8;
      --primary-light: #eff6ff;
      --primary-border: #bfdbfe;
      --accent: #2563eb;
      --accent-gold: #f59e0b;
      --text-main: #0f172a;
      --text-muted: #475569;
      --text-light: #64748b;
      --bg-page: #f8fafc;
      --bg-card: #ffffff;
      --bg-alt: #f1f5f9;
      --border-color: #e2e8f0;
      --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
      --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
      --shadow-lg: 0 10px 15px -3px rgba(30, 64, 175, 0.08), 0 4px 6px -4px rgba(30, 64, 175, 0.04);
      --radius: 12px;
      --max-width: 1200px;
      --transition: all 0.25s ease-in-out;
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-page);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    a {
      color: var(--primary);
      text-decoration: none;
      transition: var(--transition);
    }

    a:hover {
      color: var(--primary-hover);
    }

    .container {
      width: 100%;
      max-width: var(--max-width);
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }

    /* 顶部导航 */
    .header-nav {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.96);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }

    .nav-brand {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .nav-brand img.ai-page-logo {
      height: 40px;
      width: auto;
      object-fit: contain;
    }

    .brand-title {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.5px;
    }

    .nav-links {
      display: flex;
      align-items: center;
      list-style: none;
      gap: 0;
    }

    .nav-links li a {
      display: inline-block;
      padding: 8px 12px;
      font-size: 14px;
      font-weight: 500;
      color: var(--text-muted);
      border-radius: 6px;
    }

    .nav-links li a:hover,
    .nav-links li a.active {
      color: var(--primary);
      background-color: var(--primary-light);
    }

    .nav-actions {
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 20px;
      font-size: 14px;
      font-weight: 600;
      border-radius: 8px;
      border: 1px solid transparent;
      cursor: pointer;
      transition: var(--transition);
      text-align: center;
      line-height: 1.2;
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
      color: #ffffff !important;
      box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
    }

    .btn-primary:hover {
      background: linear-gradient(135deg, #1d4ed8 0%, #1e40af 100%);
      box-shadow: 0 6px 14px rgba(37, 99, 235, 0.35);
      transform: translateY(-1px);
    }

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

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

    .btn-lg {
      padding: 14px 28px;
      font-size: 16px;
      border-radius: 10px;
    }

    .mobile-menu-toggle {
      display: none;
      background: none;
      border: 1px solid var(--border-color);
      border-radius: 6px;
      padding: 8px;
      cursor: pointer;
      color: var(--text-main);
    }

    /* 首屏 Hero 区域 */
    .hero-section {
      background: linear-gradient(180deg, #eff6ff 0%, #f8fafc 100%);
      padding: 80px 0 60px;
      position: relative;
      overflow: hidden;
      border-bottom: 1px solid var(--border-color);
    }

    .hero-content {
      text-align: center;
      max-width: 900px;
      margin: 0 auto;
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 6px 14px;
      background: #dbeafe;
      color: var(--primary);
      font-size: 13px;
      font-weight: 600;
      border-radius: 50px;
      margin-bottom: 20px;
      border: 1px solid #bfdbfe;
    }

    .hero-title {
      font-size: 42px;
      font-weight: 800;
      color: #0f172a;
      line-height: 1.25;
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }

    .hero-subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 36px;
      line-height: 1.6;
    }

    .hero-cta {
      display: flex;
      justify-content: center;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 48px;
    }

    .hero-stats {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      margin-top: 40px;
      padding-top: 36px;
      border-top: 1px solid #e2e8f0;
    }

    .stat-item {
      text-align: center;
      background: #ffffff;
      padding: 16px;
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    .stat-value {
      font-size: 28px;
      font-weight: 800;
      color: var(--primary);
      display: block;
      margin-bottom: 4px;
    }

    .stat-label {
      font-size: 13px;
      color: var(--text-light);
    }

    /* 通用分块样式 */
    .section {
      padding: 70px 0;
      position: relative;
    }

    .section-alt {
      background-color: var(--bg-alt);
    }

    .section-header {
      text-align: center;
      max-width: 760px;
      margin: 0 auto 48px;
    }

    .section-tag {
      font-size: 13px;
      font-weight: 700;
      color: var(--accent);
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 8px;
      display: block;
    }

    .section-title {
      font-size: 32px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 12px;
    }

    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
    }

    /* 网格与卡片 */
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }

    .card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }

    .card:hover {
      box-shadow: var(--shadow-lg);
      transform: translateY(-3px);
      border-color: var(--primary-border);
    }

    .card-icon {
      width: 48px;
      height: 48px;
      border-radius: 10px;
      background: var(--primary-light);
      color: var(--primary);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 16px;
    }

    .card-title {
      font-size: 18px;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text-main);
    }

    .card-desc {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.6;
      flex-grow: 1;
    }

    /* 模型矩阵徽章云 */
    .model-tags {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin-top: 16px;
    }

    .model-tag {
      font-size: 12px;
      padding: 4px 10px;
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      color: #334155;
      font-weight: 500;
    }

    /* 流程步骤 */
    .steps-container {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      position: relative;
    }

    .step-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
      text-align: center;
      position: relative;
    }

    .step-num {
      width: 36px;
      height: 36px;
      border-radius: 50%;
      background: var(--primary);
      color: #ffffff;
      font-weight: 700;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 14px;
    }

    /* 对比表格 */
    .table-container {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow-x: auto;
      box-shadow: var(--shadow-sm);
    }

    .eval-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
      min-width: 650px;
    }

    .eval-table th,
    .eval-table td {
      padding: 16px 20px;
      border-bottom: 1px solid var(--border-color);
      font-size: 14px;
    }

    .eval-table th {
      background: #f8fafc;
      font-weight: 700;
      color: var(--text-main);
    }

    .eval-highlight {
      background: #f0fdf4;
      font-weight: 600;
      color: var(--primary);
    }

    .rating-banner {
      background: linear-gradient(135deg, #1e3a8a 0%, #1e40af 100%);
      color: #ffffff;
      padding: 24px;
      border-radius: var(--radius);
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 24px;
      flex-wrap: wrap;
      gap: 16px;
    }

    .score-badge {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .score-num {
      font-size: 40px;
      font-weight: 900;
      color: #fbbf24;
      line-height: 1;
    }

    /* 案例展示 */
    .case-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow: hidden;
      display: flex;
      flex-direction: column;
    }

    .case-img-wrap {
      width: 100%;
      aspect-ratio: 16 / 9;
      overflow: hidden;
      background: #e2e8f0;
    }

    .case-img-wrap.square {
      aspect-ratio: 1 / 1;
    }

    .case-img-wrap img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: var(--transition);
    }

    .case-card:hover .case-img-wrap img {
      transform: scale(1.03);
    }

    .case-body {
      padding: 20px;
      flex-grow: 1;
    }

    /* FAQ 折叠面板 */
    .faq-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      margin-bottom: 12px;
      overflow: hidden;
    }

    .faq-question {
      padding: 18px 22px;
      font-size: 16px;
      font-weight: 600;
      color: var(--text-main);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
    }

    .faq-question:hover {
      background-color: #f8fafc;
    }

    .faq-icon {
      font-size: 18px;
      transition: transform 0.25s ease;
      color: var(--primary);
    }

    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }

    .faq-answer {
      padding: 0 22px;
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.7;
    }

    .faq-item.active .faq-answer {
      padding: 0 22px 18px 22px;
      max-height: 300px;
    }

    /* 用户评论 */
    .review-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 22px;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .review-user {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: 16px;
    }

    .review-avatar {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: #dbeafe;
      color: var(--primary);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
    }

    .review-name {
      font-size: 14px;
      font-weight: 700;
      color: var(--text-main);
    }

    .review-title {
      font-size: 12px;
      color: var(--text-light);
    }

    /* 文章列表 */
    .article-box {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
    }

    .article-links-list {
      list-style: none;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 12px;
      margin-top: 16px;
    }

    .article-links-list li a {
      display: block;
      padding: 12px 16px;
      background: #f8fafc;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      font-size: 14px;
      color: var(--text-main);
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .article-links-list li a:hover {
      background: var(--primary-light);
      border-color: var(--primary-border);
      color: var(--primary);
    }

    /* 表单与联系 */
    .contact-layout {
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 32px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 36px;
      box-shadow: var(--shadow-sm);
    }

    .contact-info-list {
      list-style: none;
      margin: 20px 0;
    }

    .contact-info-list li {
      margin-bottom: 12px;
      font-size: 14px;
      color: var(--text-muted);
    }

    .contact-info-list strong {
      color: var(--text-main);
    }

    .form-group {
      margin-bottom: 18px;
    }

    .form-label {
      display: block;
      font-size: 14px;
      font-weight: 600;
      margin-bottom: 6px;
      color: var(--text-main);
    }

    .form-control {
      width: 100%;
      padding: 10px 14px;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      font-size: 14px;
      outline: none;
      transition: var(--transition);
      background: #f8fafc;
    }

    .form-control:focus {
      border-color: var(--primary);
      background: #ffffff;
      box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
    }

    textarea.form-control {
      resize: vertical;
      min-height: 100px;
    }

    .qr-container {
      display: inline-block;
      padding: 10px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      margin-top: 12px;
      text-align: center;
    }

    .qr-container img {
      width: 120px;
      height: 120px;
      display: block;
      margin: 0 auto 6px;
      object-fit: contain;
    }

    /* 页脚 */
    .site-footer {
      background: #0f172a;
      color: #94a3b8;
      padding: 48px 0 24px;
      font-size: 14px;
      border-top: 1px solid #1e293b;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 32px;
      margin-bottom: 36px;
    }

    .footer-title {
      font-size: 16px;
      font-weight: 700;
      color: #f8fafc;
      margin-bottom: 16px;
    }

    .footer-links {
      list-style: none;
    }

    .footer-links li {
      margin-bottom: 8px;
    }

    .footer-links a {
      color: #94a3b8;
    }

    .footer-links a:hover {
      color: #ffffff;
    }

    .friend-links-wrap {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
    }

    .friend-links-wrap a {
      color: #94a3b8;
      font-size: 13px;
      padding: 4px 8px;
      background: #1e293b;
      border-radius: 4px;
    }

    .friend-links-wrap a:hover {
      color: #ffffff;
      background: #334155;
    }

    .footer-bottom {
      border-top: 1px solid #1e293b;
      padding-top: 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 12px;
      font-size: 13px;
    }

    /* 浮动工具栏 */
    .float-toolbar {
      position: fixed;
      right: 20px;
      bottom: 30px;
      z-index: 999;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .float-btn {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background: #ffffff;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-md);
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      color: var(--primary);
      transition: var(--transition);
      font-size: 18px;
    }

    .float-btn:hover {
      background: var(--primary);
      color: #ffffff;
      transform: translateY(-2px);
    }

    /* 响应式适配 */
    @media (max-width: 1024px) {
      .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
      .steps-container {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      .hero-title {
        font-size: 28px;
      }
      .hero-stats {
        grid-template-columns: repeat(2, 1fr);
      }
      .grid-3,
      .grid-2 {
        grid-template-columns: 1fr;
      }
      .steps-container {
        grid-template-columns: 1fr;
      }
      .contact-layout {
        grid-template-columns: 1fr;
        padding: 20px;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: #ffffff;
        flex-direction: column;
        padding: 16px;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-md);
      }
      .nav-links.show {
        display: flex;
      }
      .mobile-menu-toggle {
        display: block;
      }
    }