:root {
      --primary: #00a896;
      --primary-hover: #028090;
      --primary-light: #e6f4f2;
      --secondary: #05668d;
      --dark: #1e293b;
      --dark-muted: #475569;
      --light-bg: #f8fafc;
      --white: #ffffff;
      --border-color: #e2e8f0;
      --accent: #f0fdfa;
      --shadow: 0 10px 25px -5px rgba(0, 168, 150, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
      --shadow-hover: 0 20px 30px -10px rgba(0, 168, 150, 0.2);
      --radius: 12px;
      --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, sans-serif;
      background-color: var(--light-bg);
      color: var(--dark);
      line-height: 1.6;
    }

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

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

    .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-color: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
    }

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

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

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

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

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

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

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

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      font-size: 14px;
      font-weight: 600;
      border-radius: 8px;
      cursor: pointer;
      border: 1px solid transparent;
      transition: var(--transition);
      white-space: nowrap;
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
      color: var(--white) !important;
      box-shadow: 0 4px 12px rgba(0, 168, 150, 0.3);
    }

    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 18px rgba(0, 168, 150, 0.4);
    }

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

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

    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--dark);
      cursor: pointer;
    }

    /* 首屏 Hero (无任何图片) */
    .hero-section {
      padding: 90px 0 70px;
      background: radial-gradient(circle at 50% 0%, #e0f2fe 0%, #f8fafc 70%);
      text-align: center;
      position: relative;
      overflow: hidden;
    }

    .hero-section::before {
      content: '';
      position: absolute;
      top: -100px;
      left: 50%;
      transform: translateX(-50%);
      width: 600px;
      height: 600px;
      background: radial-gradient(circle, rgba(0,168,150,0.15) 0%, rgba(255,255,255,0) 70%);
      pointer-events: none;
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 6px 16px;
      background-color: var(--white);
      border: 1px solid rgba(0, 168, 150, 0.3);
      border-radius: 50px;
      font-size: 13px;
      color: var(--primary);
      font-weight: 600;
      margin-bottom: 24px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    }

    .hero-title {
      font-size: 42px;
      font-weight: 800;
      color: var(--dark);
      letter-spacing: -0.5px;
      margin-bottom: 20px;
      line-height: 1.25;
    }

    .hero-subtitle {
      font-size: 18px;
      color: var(--dark-muted);
      max-width: 840px;
      margin: 0 auto 36px;
      line-height: 1.7;
    }

    .hero-btns {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 16px;
      margin-bottom: 50px;
    }

    .hero-btn-main {
      padding: 14px 36px;
      font-size: 16px;
    }

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

    .stat-card {
      background: var(--white);
      padding: 24px 20px;
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow);
      transition: var(--transition);
    }

    .stat-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }

    .stat-number {
      font-size: 32px;
      font-weight: 800;
      color: var(--primary);
      margin-bottom: 4px;
    }

    .stat-label {
      font-size: 14px;
      color: var(--dark-muted);
    }

    /* 通用 Section 样式 */
    .section {
      padding: 80px 0;
    }

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

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

    .section-header {
      text-align: center;
      max-width: 760px;
      margin: 0 auto 50px;
    }

    .section-subtitle {
      font-size: 13px;
      text-transform: uppercase;
      letter-spacing: 1.5px;
      color: var(--primary);
      font-weight: 700;
      margin-bottom: 8px;
      display: block;
    }

    .section-title {
      font-size: 32px;
      font-weight: 700;
      color: var(--dark);
      margin-bottom: 16px;
    }

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

    /* 服务与能力网格 */
    .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(--white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 28px;
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }

    .feature-card:hover {
      border-color: var(--primary);
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    .feature-icon {
      width: 48px;
      height: 48px;
      background-color: var(--primary-light);
      color: var(--primary);
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      font-weight: bold;
      margin-bottom: 18px;
    }

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

    .feature-text {
      font-size: 14px;
      color: var(--dark-muted);
      flex-grow: 1;
    }

    .model-tags {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin-top: 15px;
    }

    .model-tag {
      background-color: #f1f5f9;
      color: #334155;
      font-size: 12px;
      padding: 4px 10px;
      border-radius: 4px;
    }

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

    .step-card {
      background: var(--white);
      border: 1px solid var(--border-color);
      padding: 24px;
      border-radius: var(--radius);
      position: relative;
    }

    .step-number {
      font-size: 36px;
      font-weight: 900;
      color: var(--primary-light);
      position: absolute;
      top: 16px;
      right: 20px;
    }

    .step-title {
      font-size: 16px;
      font-weight: 700;
      margin-bottom: 8px;
      color: var(--dark);
    }

    .step-desc {
      font-size: 13px;
      color: var(--dark-muted);
    }

    /* 案例中心展示 */
    .case-card {
      background: var(--white);
      border-radius: var(--radius);
      overflow: hidden;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow);
    }

    .case-img-wrap {
      width: 100%;
      overflow: hidden;
      background-color: #e2e8f0;
    }

    .case-content {
      padding: 20px;
    }

    .case-title {
      font-size: 16px;
      font-weight: 700;
      margin-bottom: 6px;
    }

    .case-desc {
      font-size: 13px;
      color: var(--dark-muted);
    }

    /* 对比表格 */
    .comparison-wrapper {
      background: var(--white);
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      padding: 30px;
      box-shadow: var(--shadow);
    }

    .comparison-badge {
      display: flex;
      align-items: center;
      justify-content: space-between;
      background: linear-gradient(90deg, #e6f4f2 0%, #ffffff 100%);
      padding: 20px 24px;
      border-radius: 8px;
      margin-bottom: 24px;
      border-left: 4px solid var(--primary);
    }

    .score-box {
      text-align: right;
    }

    .score-val {
      font-size: 28px;
      font-weight: 800;
      color: var(--primary);
    }

    .score-stars {
      color: #f59e0b;
      font-size: 18px;
    }

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

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

    .comparison-table th {
      background-color: #f8fafc;
      font-weight: 700;
      color: var(--dark);
    }

    .highlight-cell {
      background-color: var(--primary-light);
      font-weight: 700;
      color: var(--primary-hover);
    }

    /* Token 比价表 */
    .token-table {
      width: 100%;
      border-collapse: collapse;
      background: var(--white);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--shadow);
    }

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

    .token-table th {
      background-color: var(--secondary);
      color: var(--white);
    }

    .price-discount {
      color: var(--primary);
      font-weight: 700;
    }

    /* 客户评论 */
    .review-card {
      background: var(--white);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
      box-shadow: var(--shadow);
    }

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

    .avatar-placeholder {
      width: 44px;
      height: 44px;
      border-radius: 50%;
      background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
      color: var(--white);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 16px;
    }

    .user-info h4 {
      font-size: 15px;
      font-weight: 700;
    }

    .user-info p {
      font-size: 12px;
      color: var(--dark-muted);
    }

    .review-text {
      font-size: 14px;
      color: var(--dark);
      line-height: 1.6;
    }

    /* FAQ 折叠 */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 14px;
      max-width: 900px;
      margin: 0 auto;
    }

    .faq-item {
      background: var(--white);
      border: 1px solid var(--border-color);
      border-radius: 8px;
      overflow: hidden;
    }

    .faq-question {
      padding: 18px 24px;
      font-size: 16px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background-color: var(--white);
      transition: var(--transition);
    }

    .faq-question:hover {
      background-color: var(--primary-light);
    }

    .faq-answer {
      padding: 0 24px 18px;
      font-size: 14px;
      color: var(--dark-muted);
      display: none;
      line-height: 1.7;
    }

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

    .faq-icon {
      font-size: 18px;
      transition: transform 0.3s;
    }

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

    /* 文章列表组件 */
    .article-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 12px;
      background: var(--white);
      padding: 24px;
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
    }

    .article-item {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding-bottom: 12px;
      border-bottom: 1px dashed var(--border-color);
    }

    .article-item:last-child {
      border-bottom: none;
      padding-bottom: 0;
    }

    .article-link {
      color: var(--dark);
      font-size: 15px;
      font-weight: 500;
    }

    .article-link:hover {
      color: var(--primary);
    }

    /* 表单区 */
    .form-wrapper {
      background: var(--white);
      border-radius: var(--radius);
      padding: 36px;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow);
    }

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

    .form-label {
      display: block;
      font-size: 14px;
      font-weight: 600;
      margin-bottom: 8px;
      color: var(--dark);
    }

    .form-control {
      width: 100%;
      padding: 12px 16px;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      font-size: 14px;
      transition: var(--transition);
    }

    .form-control:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(0, 168, 150, 0.15);
    }

    textarea.form-control {
      resize: vertical;
      min-height: 110px;
    }

    /* 页脚 */
    .site-footer {
      background-color: #0f172a;
      color: #94a3b8;
      padding: 60px 0 30px;
      font-size: 14px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
      margin-bottom: 40px;
    }

    .footer-brand {
      color: #ffffff;
      font-weight: 700;
      font-size: 20px;
      margin-bottom: 16px;
    }

    .footer-title {
      color: #ffffff;
      font-size: 16px;
      font-weight: 600;
      margin-bottom: 18px;
    }

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

    .footer-links li {
      margin-bottom: 10px;
    }

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

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

    .friend-links {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 10px;
    }

    .friend-links a {
      color: #94a3b8;
      background: #1e293b;
      padding: 4px 10px;
      border-radius: 4px;
      font-size: 12px;
    }

    .friend-links a:hover {
      color: #ffffff;
      background: var(--primary);
    }

    .footer-bottom {
      border-top: 1px solid #1e293b;
      padding-top: 24px;
      text-align: center;
      color: #64748b;
      font-size: 13px;
    }

    /* 浮动客服 */
    .float-kefu {
      position: fixed;
      right: 20px;
      bottom: 30px;
      z-index: 999;
      background: var(--white);
      border-radius: 12px;
      padding: 12px;
      box-shadow: 0 10px 25px rgba(0,0,0,0.15);
      border: 1px solid var(--border-color);
      text-align: center;
      width: 130px;
    }

    .float-kefu img {
      width: 100px;
      height: 100px;
      border-radius: 6px;
      margin-bottom: 6px;
    }

    .float-kefu p {
      font-size: 12px;
      color: var(--dark);
      font-weight: 600;
    }

    /* 响应式适配 */
    @media (max-width: 992px) {
      .hero-title { font-size: 32px; }
      .hero-stats { grid-template-columns: repeat(2, 1fr); }
      .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .workflow-steps { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
        border-bottom: 1px solid var(--border-color);
      }
      .nav-links.show { display: flex; }
      .menu-toggle { display: block; }
      .hero-btns { flex-direction: column; }
      .grid-3, .grid-4, .grid-2, .workflow-steps { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .comparison-table { display: block; overflow-x: auto; }
      .float-kefu { display: none; } /* 移动端隐藏浮动以避挡 */
    }