:root {
      --primary: #4f46e5;
      --primary-light: #6366f1;
      --accent-rainbow: linear-gradient(135deg, #ff4b4b 0%, #ff8533 20%, #ffc107 40%, #00c853 60%, #00b0ff 80%, #7c4dff 100%);
      --accent-soft: linear-gradient(135deg, rgba(79, 70, 229, 0.08) 0%, rgba(236, 72, 153, 0.08) 50%, rgba(59, 130, 246, 0.08) 100%);
      --text-main: #1e293b;
      --text-muted: #64748b;
      --text-heading: #0f172a;
      --bg-page: #f8fafc;
      --bg-card: #ffffff;
      --border-color: #e2e8f0;
      --radius-sm: 8px;
      --radius-md: 14px;
      --radius-lg: 20px;
      --shadow-sm: 0 2px 4px rgba(0,0,0,0.03);
      --shadow-md: 0 10px 25px -5px rgba(15, 23, 42, 0.06), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
      --shadow-lg: 0 20px 30px -10px rgba(79, 70, 229, 0.12);
      --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

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

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

    body {
      background-color: var(--bg-page);
      color: var(--text-main);
      overflow-x: hidden;
    }

    .container {
      width: 100%;
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }

    .rainbow-bar {
      height: 4px;
      background: var(--accent-rainbow);
      width: 100%;
    }

    /* 顶部导航 */
    .site-header {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      position: sticky;
      top: 0;
      z-index: 1000;
      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;
    }
    .brand-group {
      display: flex;
      align-items: center;
      gap: 12px;
      text-decoration: none;
    }
    .brand-group .ai-page-logo {
      height: 42px;
      width: auto;
      object-fit: contain;
    }
    .brand-title {
      font-size: 1.25rem;
      font-weight: 800;
      color: var(--text-heading);
      letter-spacing: -0.5px;
    }
    .nav-links {
      display: flex;
      gap: 0;
      list-style: none;
      align-items: center;
    }
    .nav-links a {
      color: var(--text-main);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.92rem;
      padding: 8px 12px;
      border-radius: var(--radius-sm);
      transition: var(--transition);
    }
    .nav-links a:hover {
      color: var(--primary);
      background-color: rgba(79, 70, 229, 0.05);
    }
    .nav-actions {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      font-size: 0.95rem;
      font-weight: 600;
      border-radius: var(--radius-md);
      text-decoration: none;
      cursor: pointer;
      border: 1px solid transparent;
      transition: var(--transition);
      line-height: 1.4;
    }
    .btn-primary {
      background: var(--accent-rainbow);
      color: #ffffff;
      box-shadow: 0 4px 15px rgba(255, 75, 75, 0.25);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(79, 70, 229, 0.35);
      color: #ffffff;
    }
    .btn-secondary {
      background: #ffffff;
      color: var(--primary);
      border-color: var(--primary);
    }
    .btn-secondary:hover {
      background: rgba(79, 70, 229, 0.05);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 1.5rem;
      cursor: pointer;
      color: var(--text-heading);
      padding: 4px;
    }

    /* 章节通用 */
    .section {
      padding: 70px 0;
      position: relative;
    }
    .section-alt {
      background: #ffffff;
    }
    .section-title-wrap {
      text-align: center;
      max-width: 760px;
      margin: 0 auto 50px;
    }
    .section-badge {
      display: inline-block;
      padding: 4px 14px;
      background: var(--accent-soft);
      border: 1px solid rgba(79, 70, 229, 0.2);
      border-radius: 50px;
      font-size: 0.82rem;
      font-weight: 700;
      color: var(--primary);
      text-transform: uppercase;
      margin-bottom: 12px;
    }
    .section-title {
      font-size: 2.1rem;
      font-weight: 800;
      color: var(--text-heading);
      letter-spacing: -0.5px;
      margin-bottom: 14px;
    }
    .section-desc {
      font-size: 1rem;
      color: var(--text-muted);
      line-height: 1.7;
    }

    /* Hero 首屏 - 纯代码几何科技风 无图片 */
    .hero-section {
      padding: 90px 0 70px;
      background: radial-gradient(circle at 10% 20%, rgba(255, 75, 75, 0.04) 0%, rgba(0, 176, 255, 0.04) 90%), #ffffff;
      border-bottom: 1px solid var(--border-color);
      position: relative;
      overflow: hidden;
    }
    .hero-content {
      text-align: center;
      max-width: 900px;
      margin: 0 auto;
      position: relative;
      z-index: 2;
    }
    .hero-tagline {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 6px 18px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: 100px;
      box-shadow: var(--shadow-sm);
      font-size: 0.9rem;
      color: var(--text-main);
      font-weight: 600;
      margin-bottom: 24px;
    }
    .hero-tagline span {
      background: var(--accent-rainbow);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      font-weight: 800;
    }
    .hero-title {
      font-size: 2.8rem;
      font-weight: 900;
      line-height: 1.25;
      color: var(--text-heading);
      margin-bottom: 20px;
      letter-spacing: -1px;
    }
    .hero-subtitle {
      font-size: 1.15rem;
      color: var(--text-muted);
      line-height: 1.75;
      margin-bottom: 36px;
      max-width: 780px;
      margin-left: auto;
      margin-right: auto;
    }
    .hero-cta-group {
      display: flex;
      gap: 16px;
      justify-content: center;
      flex-wrap: wrap;
      margin-bottom: 48px;
    }
    .hero-cta-btn-main {
      font-size: 1.05rem;
      padding: 14px 34px;
      border-radius: 50px;
    }
    .hero-tags-box {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 10px;
      margin-top: 20px;
    }
    .hero-tag-item {
      background: var(--bg-page);
      border: 1px solid var(--border-color);
      padding: 6px 14px;
      border-radius: 8px;
      font-size: 0.85rem;
      color: var(--text-muted);
      font-weight: 500;
    }

    /* 数据指标 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      margin-top: -30px;
      position: relative;
      z-index: 10;
    }
    .metric-card {
      background: #ffffff;
      padding: 24px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-md);
      text-align: center;
      transition: var(--transition);
    }
    .metric-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
    }
    .metric-num {
      font-size: 2.2rem;
      font-weight: 800;
      color: var(--primary);
      margin-bottom: 6px;
      line-height: 1.1;
    }
    .metric-label {
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-heading);
      margin-bottom: 4px;
    }
    .metric-sub {
      font-size: 0.78rem;
      color: var(--text-muted);
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 30px;
    }

    .feature-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 26px;
      transition: var(--transition);
      display: flex;
      flex-direction: column;
      height: 100%;
    }
    .feature-card:hover {
      transform: translateY(-5px);
      border-color: rgba(79, 70, 229, 0.3);
      box-shadow: var(--shadow-md);
    }
    .feature-icon-box {
      width: 46px;
      height: 46px;
      border-radius: 12px;
      background: var(--accent-soft);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.3rem;
      color: var(--primary);
      margin-bottom: 16px;
      border: 1px solid rgba(79, 70, 229, 0.15);
    }
    .feature-title {
      font-size: 1.15rem;
      font-weight: 700;
      color: var(--text-heading);
      margin-bottom: 10px;
    }
    .feature-desc {
      font-size: 0.92rem;
      color: var(--text-muted);
      line-height: 1.65;
      flex-grow: 1;
    }
    .feature-badge {
      align-self: flex-start;
      margin-top: 14px;
      font-size: 0.75rem;
      padding: 3px 10px;
      background: var(--bg-page);
      border: 1px solid var(--border-color);
      border-radius: 4px;
      color: var(--text-muted);
      font-weight: 600;
    }

    /* 流程与网络 */
    .flow-steps {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      position: relative;
    }
    .flow-step-card {
      background: #ffffff;
      padding: 24px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      position: relative;
    }
    .flow-num {
      width: 36px;
      height: 36px;
      border-radius: 50%;
      background: var(--accent-rainbow);
      color: #fff;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
      font-size: 1rem;
      margin-bottom: 14px;
    }

    /* 对比表格 */
    .compare-container {
      background: #ffffff;
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }
    .compare-header-box {
      background: var(--accent-soft);
      padding: 24px 30px;
      border-bottom: 1px solid var(--border-color);
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 16px;
    }
    .score-badge {
      display: flex;
      align-items: center;
      gap: 12px;
      background: #ffffff;
      padding: 8px 18px;
      border-radius: 50px;
      border: 1px solid rgba(79, 70, 229, 0.2);
    }
    .score-badge .score-val {
      font-size: 1.4rem;
      font-weight: 800;
      color: #ff4b4b;
    }
    .score-badge .stars {
      color: #ffc107;
      font-size: 1.1rem;
      letter-spacing: 2px;
    }
    .table-responsive {
      width: 100%;
      overflow-x: auto;
    }
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
    }
    .compare-table th, .compare-table td {
      padding: 18px 24px;
      border-bottom: 1px solid var(--border-color);
      font-size: 0.94rem;
    }
    .compare-table th {
      background: #f8fafc;
      color: var(--text-heading);
      font-weight: 700;
    }
    .compare-table tr:last-child td {
      border-bottom: none;
    }
    .col-highlight {
      background: rgba(79, 70, 229, 0.02);
      font-weight: 600;
      color: var(--primary);
    }

    /* 案例展示 */
    .case-card {
      background: #ffffff;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .case-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    .case-img-wrap {
      width: 100%;
      aspect-ratio: 16 / 9;
      background: #f1f5f9;
      overflow: hidden;
    }
    .case-img-wrap.square {
      aspect-ratio: 1 / 1;
    }
    .case-img-wrap img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      display: block;
      transition: var(--transition);
    }
    .case-card:hover .case-img-wrap img {
      transform: scale(1.03);
    }
    .case-body {
      padding: 20px;
      flex-grow: 1;
      display: flex;
      flex-direction: column;
    }

    /* 用户评论 */
    .testimonial-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .testi-header {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 14px;
    }
    .testi-avatar {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: var(--accent-rainbow);
      color: #ffffff;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.1rem;
    }
    .testi-meta h4 {
      font-size: 0.98rem;
      color: var(--text-heading);
    }
    .testi-meta p {
      font-size: 0.8rem;
      color: var(--text-muted);
    }
    .testi-text {
      font-size: 0.92rem;
      color: var(--text-main);
      line-height: 1.6;
    }

    /* FAQ 折叠面板 */
    .faq-list {
      max-width: 860px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 14px;
    }
    .faq-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
      transition: var(--transition);
    }
    .faq-question {
      padding: 20px 24px;
      font-size: 1.05rem;
      font-weight: 700;
      color: var(--text-heading);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
    }
    .faq-question::after {
      content: '+';
      font-size: 1.4rem;
      font-weight: 400;
      color: var(--primary);
      transition: transform 0.3s;
    }
    .faq-item.active .faq-question::after {
      transform: rotate(45deg);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out;
      background: #fafbfc;
      border-top: 1px solid transparent;
    }
    .faq-item.active .faq-answer {
      border-top-color: var(--border-color);
    }
    .faq-answer-inner {
      padding: 20px 24px;
      font-size: 0.94rem;
      color: var(--text-muted);
      line-height: 1.7;
    }

    /* 表单与联系 */
    .form-wrapper {
      background: #ffffff;
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      padding: 36px;
      box-shadow: var(--shadow-md);
    }
    .form-group {
      margin-bottom: 20px;
    }
    .form-label {
      display: block;
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-heading);
      margin-bottom: 8px;
    }
    .form-control {
      width: 100%;
      padding: 12px 16px;
      border-radius: var(--radius-sm);
      border: 1px solid var(--border-color);
      font-size: 0.95rem;
      color: var(--text-main);
      background: var(--bg-page);
      outline: none;
      transition: var(--transition);
    }
    .form-control:focus {
      border-color: var(--primary);
      background: #ffffff;
      box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
    }
    textarea.form-control {
      resize: vertical;
      min-height: 110px;
    }

    .contact-card-box {
      display: flex;
      flex-direction: column;
      gap: 20px;
    }
    .contact-info-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 20px;
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .contact-qr-box {
      text-align: center;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
    }
    .contact-qr-box img {
      width: 140px;
      height: 140px;
      object-fit: contain;
      margin-bottom: 12px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
    }

    /* 文章与友情链接 */
    .article-link-list {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
    }
    .article-link-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      padding: 10px 18px;
      border-radius: var(--radius-sm);
      text-decoration: none;
      color: var(--text-heading);
      font-size: 0.9rem;
      font-weight: 500;
      transition: var(--transition);
    }
    .article-link-item:hover {
      border-color: var(--primary);
      color: var(--primary);
      transform: translateY(-2px);
    }

    .friend-links-wrap {
      display: flex;
      flex-wrap: wrap;
      gap: 14px;
      align-items: center;
    }
    .friend-links-wrap a {
      color: var(--text-muted);
      text-decoration: none;
      font-size: 0.88rem;
      transition: var(--transition);
    }
    .friend-links-wrap a:hover {
      color: var(--primary);
    }

    /* 页脚 */
    .site-footer {
      background: #0f172a;
      color: #94a3b8;
      padding: 60px 0 30px;
      font-size: 0.9rem;
      border-top: 1px solid #1e293b;
    }
    .site-footer h5 {
      color: #ffffff;
      font-size: 1.05rem;
      margin-bottom: 18px;
      font-weight: 700;
    }
    .site-footer a {
      color: #94a3b8;
      text-decoration: none;
      transition: var(--transition);
    }
    .site-footer a:hover {
      color: #ffffff;
    }
    .footer-bottom {
      border-top: 1px solid #1e293b;
      margin-top: 40px;
      padding-top: 24px;
      text-align: center;
      font-size: 0.85rem;
    }

    /* 浮动客服 */
    .floating-service {
      position: fixed;
      right: 24px;
      bottom: 30px;
      z-index: 999;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .float-btn {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background: #ffffff;
      color: var(--primary);
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 4px 15px rgba(0,0,0,0.15);
      cursor: pointer;
      text-decoration: none;
      border: 1px solid var(--border-color);
      transition: var(--transition);
      font-size: 1.2rem;
    }
    .float-btn:hover {
      transform: scale(1.08);
      background: var(--primary);
      color: #ffffff;
    }

    /* 响应式调整 */
    @media (max-width: 992px) {
      .grid-4, .metrics-grid, .flow-steps {
        grid-template-columns: repeat(2, 1fr);
      }
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
      .hero-title {
        font-size: 2.2rem;
      }
      .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: #ffffff;
        border-bottom: 1px solid var(--border-color);
        padding: 20px;
        box-shadow: var(--shadow-md);
      }
      .nav-links.active {
        display: flex;
      }
      .menu-toggle {
        display: block;
      }
    }

    @media (max-width: 768px) {
      .grid-4, .grid-3, .grid-2, .metrics-grid, .flow-steps {
        grid-template-columns: 1fr;
      }
      .hero-section {
        padding: 50px 0 40px;
      }
      .hero-title {
        font-size: 1.8rem;
      }
      .hero-cta-group {
        flex-direction: column;
      }
      .section {
        padding: 50px 0;
      }
    }