:root {
      --primary-color: #2563eb;
      --primary-hover: #1d4ed8;
      --accent-color: #06b6d4;
      --bg-main: #f8fafc;
      --bg-card: #ffffff;
      --text-main: #0f172a;
      --text-muted: #475569;
      --border-color: #e2e8f0;
      --shadow-sm: 0 2px 4px rgba(0,0,0,0.04);
      --shadow-md: 0 10px 25px -5px rgba(37,99,235,0.08);
      --shadow-lg: 0 20px 30px -10px rgba(0,0,0,0.1);
      --radius-sm: 8px;
      --radius-md: 14px;
      --radius-lg: 20px;
    }

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

    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      background-color: var(--bg-main);
      color: var(--text-main);
      line-height: 1.6;
    }

    body {
      overflow-x: hidden;
    }

    /* 容器规范 */
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
      width: 100%;
    }

    /* 顶部导航 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

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

    .logo-box {
      display: flex;
      align-items: center;
      gap: 12px;
      text-decoration: none;
    }

    .ai-page-logo {
      height: 40px;
      width: auto;
    }

    .brand-name {
      font-size: 1.3rem;
      font-weight: 800;
      color: var(--primary-color);
      letter-spacing: -0.5px;
    }

    .nav-links {
      display: flex;
      align-items: center;
      list-style: none;
      gap: 0; /* 严格要求 */
    }

    .nav-links li a {
      display: inline-block;
      padding: 8px 14px;
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text-main);
      text-decoration: none;
      transition: color 0.2s ease;
    }

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

    .header-actions {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    /* 按钮通用 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      text-decoration: none;
      transition: all 0.25s ease;
      cursor: pointer;
      border: 1px solid transparent;
      font-size: 0.95rem;
    }

    .btn-primary {
      background-color: var(--primary-color);
      color: #ffffff;
      box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
    }

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

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

    .btn-secondary:hover {
      background-color: #eff6ff;
      transform: translateY(-2px);
    }

    .btn-accent {
      background: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
      color: #ffffff;
    }

    .btn-accent:hover {
      opacity: 0.95;
      transform: translateY(-2px);
    }

    /* 首屏 HERO (无图片) */
    .hero-section {
      padding: 90px 0 70px;
      background: radial-gradient(circle at 50% 20%, #eff6ff 0%, #ffffff 80%);
      border-bottom: 1px solid var(--border-color);
      text-align: center;
    }

    .hero-badge {
      display: inline-block;
      padding: 6px 16px;
      background-color: #dbeafe;
      color: var(--primary-color);
      border-radius: 50px;
      font-size: 0.88rem;
      font-weight: 600;
      margin-bottom: 24px;
    }

    .hero-title {
      font-size: 2.2rem;
      font-weight: 900;
      color: var(--text-main);
      margin-bottom: 20px;
      line-height: 1.25;
      letter-spacing: -0.5px;
    }

    .hero-subtitle {
      font-size: 1.15rem;
      color: var(--text-muted);
      max-width: 800px;
      margin: 0 auto 36px;
      line-height: 1.7;
    }

    .hero-cta {
      display: flex;
      justify-content: center;
      gap: 16px;
      margin-bottom: 50px;
      flex-wrap: wrap;
    }

    .hero-stats {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
      gap: 20px;
      max-width: 1000px;
      margin: 0 auto;
    }

    .stat-card {
      background: #ffffff;
      padding: 24px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    .stat-num {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--primary-color);
    }

    .stat-label {
      font-size: 0.9rem;
      color: var(--text-muted);
      margin-top: 4px;
    }

    /* 区域通用规范 */
    .section-padding {
      padding: 80px 0;
    }

    .section-title-wrap {
      text-align: center;
      max-width: 750px;
      margin: 0 auto 50px;
    }

    .section-tag {
      color: var(--primary-color);
      font-size: 0.9rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 8px;
      display: block;
    }

    .section-title {
      font-size: 1.9rem;
      font-weight: 800;
      color: var(--text-main);
    }

    .section-desc {
      color: var(--text-muted);
      margin-top: 12px;
      font-size: 1rem;
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
      gap: 24px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 20px;
    }

    .feature-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 28px;
      transition: all 0.3s ease;
      box-shadow: var(--shadow-sm);
    }

    .feature-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-md);
      border-color: #bfdbfe;
    }

    .card-icon {
      width: 48px;
      height: 48px;
      background: #eff6ff;
      color: var(--primary-color);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: bold;
      font-size: 1.2rem;
      margin-bottom: 18px;
    }

    .card-title {
      font-size: 1.2rem;
      font-weight: 700;
      margin-bottom: 10px;
    }

    .card-text {
      font-size: 0.95rem;
      color: var(--text-muted);
      line-height: 1.6;
    }

    /* 包含图片的案例区 */
    .media-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }

    .media-img-wrap {
      width: 100%;
      overflow: hidden;
      background: #f1f5f9;
    }

    .media-body {
      padding: 20px;
    }

    /* 对比评测 */
    .eval-box {
      background: #ffffff;
      border: 2px solid var(--primary-color);
      border-radius: var(--radius-lg);
      padding: 36px;
      box-shadow: var(--shadow-md);
    }

    .eval-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      border-bottom: 1px solid var(--border-color);
      padding-bottom: 20px;
      margin-bottom: 24px;
      flex-wrap: wrap;
      gap: 16px;
    }

    .eval-score {
      font-size: 2.2rem;
      font-weight: 900;
      color: var(--primary-color);
    }

    .eval-stars {
      color: #f59e0b;
      font-size: 1.2rem;
      font-weight: bold;
    }

    .table-wrap {
      overflow-x: auto;
    }

    .custom-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
    }

    .custom-table th, .custom-table td {
      padding: 14px 18px;
      border-bottom: 1px solid var(--border-color);
      font-size: 0.95rem;
    }

    .custom-table th {
      background-color: #f8fafc;
      font-weight: 700;
    }

    .custom-table tr:hover {
      background-color: #f1f5f9;
    }

    /* FAQ折叠面板 */
    .faq-list {
      max-width: 900px;
      margin: 0 auto;
    }

    .faq-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      margin-bottom: 12px;
      overflow: hidden;
    }

    .faq-title {
      padding: 18px 24px;
      font-weight: 700;
      font-size: 1.05rem;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: #ffffff;
    }

    .faq-title:hover {
      color: var(--primary-color);
    }

    .faq-content {
      padding: 0 24px 18px;
      display: none;
      color: var(--text-muted);
      font-size: 0.95rem;
      border-top: 1px dashed var(--border-color);
      padding-top: 14px;
    }

    .faq-item.active .faq-content {
      display: block;
    }

    /* 评论卡片 */
    .review-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
    }

    .review-user {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 14px;
    }

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

    .user-info h4 {
      font-size: 1rem;
      font-weight: 700;
    }

    .user-info p {
      font-size: 0.82rem;
      color: var(--text-muted);
    }

    /* 表单与联系区 */
    .contact-wrapper {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-lg);
      padding: 40px;
      box-shadow: var(--shadow-md);
    }

    .form-group {
      margin-bottom: 20px;
    }

    .form-group label {
      display: block;
      margin-bottom: 8px;
      font-weight: 600;
      font-size: 0.92rem;
    }

    .form-control {
      width: 100%;
      padding: 12px 16px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      font-size: 0.95rem;
      outline: none;
      transition: border 0.2s;
    }

    .form-control:focus {
      border-color: var(--primary-color);
    }

    textarea.form-control {
      min-height: 120px;
      resize: vertical;
    }

    .contact-info-box {
      display: flex;
      flex-direction: column;
      gap: 20px;
    }

    .qr-code-img {
      width: 150px;
      height: 150px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      padding: 6px;
    }

    /* 友情链接与页脚 */
    .footer-section {
      background-color: #ffffff;
      border-top: 1px solid var(--border-color);
      padding: 50px 0 30px;
      color: var(--text-main);
    }

    .friend-links-box {
      border-bottom: 1px solid var(--border-color);
      padding-bottom: 24px;
      margin-bottom: 24px;
      text-align: center;
    }

    .friend-links-box h4 {
      font-size: 1rem;
      margin-bottom: 12px;
      color: var(--text-muted);
    }

    .friend-links-box a {
      color: var(--text-muted);
      text-decoration: none;
      margin: 0 12px;
      font-size: 0.9rem;
    }

    .friend-links-box a:hover {
      color: var(--primary-color);
    }

    .footer-bottom {
      text-align: center;
      font-size: 0.9rem;
      color: var(--text-muted);
    }

    /* 移动端适配 */
    @media (max-width: 902px) {
      .header-inner {
        flex-wrap: wrap;
        height: auto;
        padding: 12px 0;
      }
      .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        align-items: flex-start;
        padding: 12px 0;
      }
      .nav-links.show {
        display: flex;
      }
      .contact-wrapper {
        grid-template-columns: 1fr;
      }
      .hero-title {
        font-size: 1.7rem;
      }
    }