:root {
      --primary-color: #1a56db;
      --primary-hover: #1343aa;
      --primary-light: #eef4ff;
      --accent-color: #0070f3;
      --accent-glow: #3b82f6;
      --cyan-bright: #06b6d4;
      --text-main: #0f172a;
      --text-sub: #334155;
      --text-muted: #64748b;
      --bg-main: #f8fafc;
      --bg-card: #ffffff;
      --bg-alt: #f1f5f9;
      --border-color: #e2e8f0;
      --border-focus: #bfdbfe;
      --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
      --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
      --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.03);
      --shadow-blue: 0 10px 25px -5px rgba(26, 86, 219, 0.18);
      --radius-sm: 6px;
      --radius-md: 10px;
      --radius-lg: 16px;
      --transition: all 0.25s ease;
    }

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

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-main);
      color: var(--text-main);
      line-height: 1.65;
      -webkit-font-smoothing: antialiased;
    }

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

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

    /* 顶部导航 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 999;
      background-color: rgba(255, 255, 255, 0.96);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }
    .nav-wrapper {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .brand-box {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .ai-page-logo {
      height: 40px;
      width: auto;
      display: block;
    }
    .brand-title {
      font-size: 1.25rem;
      font-weight: 700;
      color: var(--primary-color);
      letter-spacing: -0.5px;
    }
    .brand-tag {
      font-size: 0.75rem;
      padding: 2px 8px;
      border-radius: 999px;
      background: var(--primary-light);
      color: var(--primary-color);
      font-weight: 600;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 0;
      list-style: none;
    }
    .nav-links li a {
      color: var(--text-sub);
      font-size: 0.95rem;
      font-weight: 500;
      padding: 8px 14px;
      border-radius: var(--radius-sm);
      display: block;
    }
    .nav-links li a:hover,
    .nav-links li a.active {
      color: var(--primary-color);
      background-color: var(--primary-light);
    }

    .nav-actions {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 9px 20px;
      border-radius: var(--radius-sm);
      font-size: 0.95rem;
      font-weight: 600;
      cursor: pointer;
      border: 1px solid transparent;
      transition: var(--transition);
      text-align: center;
      white-space: nowrap;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--primary-color) 0%, #2563eb 100%);
      color: #ffffff !important;
      box-shadow: 0 4px 12px rgba(26, 86, 219, 0.25);
    }
    .btn-primary:hover {
      background: linear-gradient(135deg, #1545b6 0%, #1d4ed8 100%);
      transform: translateY(-1px);
      box-shadow: 0 6px 16px rgba(26, 86, 219, 0.35);
    }
    .btn-outline {
      background-color: #ffffff;
      border-color: var(--primary-color);
      color: var(--primary-color);
    }
    .btn-outline:hover {
      background-color: var(--primary-light);
    }
    .btn-sm {
      padding: 6px 14px;
      font-size: 0.875rem;
    }
    .btn-lg {
      padding: 13px 30px;
      font-size: 1.05rem;
    }

    .menu-toggle {
      display: none;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .menu-toggle span {
      display: block;
      width: 24px;
      height: 2px;
      background-color: var(--text-main);
      margin: 5px 0;
      transition: var(--transition);
    }

    /* 首屏 Hero：严格无图片 */
    .hero-section {
      position: relative;
      background: radial-gradient(circle at 50% 10%, #eff6ff 0%, #ffffff 80%);
      padding: 60px 0 60px;
      text-align: center;
      border-bottom: 1px solid var(--border-color);
      overflow: hidden;
    }
    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 6px 16px;
      border-radius: 999px;
      background-color: #ffffff;
      border: 1px solid #bfdbfe;
      color: var(--primary-color);
      font-size: 0.875rem;
      font-weight: 600;
      margin-bottom: 24px;
      box-shadow: var(--shadow-sm);
    }
    .hero-badge::before {
      content: "";
      width: 8px;
      height: 8px;
      background-color: #10b981;
      border-radius: 50%;
      display: inline-block;
    }
    .hero-title {
      font-size: 2.5rem;
      line-height: 1.25;
      font-weight: 800;
      color: var(--text-main);
      margin-bottom: 20px;
      letter-spacing: -0.5px;
    }
    .hero-title span {
      color: var(--primary-color);
      background: linear-gradient(120deg, #1a56db, #06b6d4);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .hero-subtitle {
      max-width: 840px;
      margin: 0 auto 36px;
      font-size: 1.15rem;
      color: var(--text-sub);
      line-height: 1.7;
    }
    .hero-cta-group {
      display: flex;
      align-items: center;
      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: 20px;
    }
    .stat-card {
      background: #ffffff;
      padding: 24px 16px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .stat-card:hover {
      transform: translateY(-3px);
      box-shadow: var(--shadow-md);
      border-color: var(--border-focus);
    }
    .stat-number {
      font-size: 2rem;
      font-weight: 800;
      color: var(--primary-color);
      line-height: 1.1;
      margin-bottom: 6px;
    }
    .stat-label {
      font-size: 0.9rem;
      color: var(--text-muted);
    }

    /* 公共区域标题 */
    .section-padding {
      padding: 70px 0;
      border-bottom: 1px solid var(--border-color);
    }
    .section-header {
      text-align: center;
      max-width: 780px;
      margin: 0 auto 48px;
    }
    .section-tag {
      display: inline-block;
      font-size: 0.85rem;
      font-weight: 700;
      color: var(--primary-color);
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 10px;
      background-color: var(--primary-light);
      padding: 4px 12px;
      border-radius: var(--radius-sm);
    }
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 14px;
    }
    .section-desc {
      font-size: 1rem;
      color: var(--text-muted);
      line-height: 1.7;
    }

    /* 模型矩阵与标签云 */
    .models-stream {
      background-color: #ffffff;
      padding: 24px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      margin-bottom: 40px;
    }
    .models-stream-title {
      font-size: 0.95rem;
      font-weight: 600;
      color: var(--text-muted);
      margin-bottom: 16px;
      text-align: center;
    }
    .tag-cloud {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
    }
    .tag-item {
      padding: 6px 14px;
      background-color: var(--bg-main);
      border: 1px solid var(--border-color);
      border-radius: 20px;
      font-size: 0.85rem;
      font-weight: 600;
      color: var(--text-sub);
      transition: var(--transition);
    }
    .tag-item:hover {
      background-color: var(--primary-light);
      border-color: var(--primary-color);
      color: var(--primary-color);
    }

    /* 网格卡片布局 */
    .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;
    }

    .feature-card {
      background-color: #ffffff;
      padding: 28px 24px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
      height: 100%;
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-blue);
      border-color: #bfdbfe;
    }
    .feature-icon-box {
      width: 48px;
      height: 48px;
      border-radius: var(--radius-sm);
      background: var(--primary-light);
      color: var(--primary-color);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.25rem;
      margin-bottom: 18px;
    }
    .feature-card h3 {
      font-size: 1.2rem;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 10px;
    }
    .feature-card p {
      font-size: 0.925rem;
      color: var(--text-sub);
      line-height: 1.6;
      flex-grow: 1;
    }
    .feature-card .card-footer-info {
      margin-top: 16px;
      padding-top: 12px;
      border-top: 1px solid #f1f5f9;
      font-size: 0.85rem;
      color: var(--primary-color);
      font-weight: 600;
    }

    /* 平台介绍与关于我们 */
    .about-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .about-content h2 {
      font-size: 1.85rem;
      color: var(--text-main);
      margin-bottom: 16px;
      font-weight: 700;
    }
    .about-content p {
      color: var(--text-sub);
      margin-bottom: 16px;
      font-size: 0.98rem;
    }
    .about-check-list {
      list-style: none;
      margin: 20px 0;
    }
    .about-check-list li {
      position: relative;
      padding-left: 26px;
      margin-bottom: 12px;
      color: var(--text-main);
      font-weight: 500;
      font-size: 0.95rem;
    }
    .about-check-list li::before {
      content: "✓";
      position: absolute;
      left: 0;
      top: 0;
      color: #10b981;
      font-weight: 800;
      font-size: 1.1rem;
    }
    .about-media-box {
      background: #ffffff;
      padding: 16px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }
    .about-media-box img {
      width: 100%;
      height: auto;
      border-radius: var(--radius-sm);
      display: block;
    }

    /* 标准流程时间线 */
    .process-timeline {
      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-md);
      padding: 24px;
      position: relative;
      transition: var(--transition);
    }
    .step-card:hover {
      border-color: var(--primary-color);
      box-shadow: var(--shadow-md);
    }
    .step-num {
      display: inline-block;
      width: 36px;
      height: 36px;
      line-height: 36px;
      background: var(--primary-color);
      color: #ffffff;
      font-weight: 700;
      border-radius: 50%;
      text-align: center;
      margin-bottom: 14px;
    }
    .step-card h3 {
      font-size: 1.1rem;
      color: var(--text-main);
      margin-bottom: 8px;
    }
    .step-card p {
      font-size: 0.88rem;
      color: var(--text-muted);
    }

    /* 对比评测表格 */
    .compare-container {
      background: #ffffff;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-md);
      overflow-x: auto;
      margin-bottom: 24px;
    }
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      min-width: 680px;
      text-align: left;
    }
    .compare-table th, 
    .compare-table td {
      padding: 18px 20px;
      border-bottom: 1px solid var(--border-color);
      font-size: 0.95rem;
    }
    .compare-table th {
      background-color: var(--bg-alt);
      color: var(--text-main);
      font-weight: 700;
    }
    .compare-table tr:last-child td {
      border-bottom: none;
    }
    .compare-table .highlight-col {
      background-color: #f0f7ff;
      font-weight: 600;
      color: var(--primary-color);
      border-left: 2px solid var(--primary-color);
      border-right: 2px solid var(--primary-color);
    }
    .score-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      background: #eff6ff;
      color: #1d4ed8;
      border: 1px solid #bfdbfe;
      padding: 4px 12px;
      border-radius: 20px;
      font-weight: 700;
      font-size: 0.9rem;
    }

    /* 案例展示 */
    .case-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-lg);
      transform: translateY(-3px);
    }
    .case-img-wrap {
      width: 100%;
      overflow: hidden;
      background-color: #f1f5f9;
    }
    .case-img-wrap img {
      width: 100%;
      height: auto;
      display: block;
      transition: transform 0.3s ease;
    }
    .case-card:hover .case-img-wrap img {
      transform: scale(1.02);
    }
    .case-body {
      padding: 20px;
    }
    .case-tag {
      font-size: 0.75rem;
      background: var(--primary-light);
      color: var(--primary-color);
      padding: 2px 8px;
      border-radius: 4px;
      font-weight: 600;
    }
    .case-body h3 {
      font-size: 1.15rem;
      margin: 10px 0 8px;
      color: var(--text-main);
    }
    .case-body p {
      font-size: 0.9rem;
      color: var(--text-muted);
    }

    /* 宣传图画廊 */
    .gallery-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
      margin-top: 24px;
    }
    .gallery-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .gallery-item img {
      width: 100%;
      height: auto;
      display: block;
    }

    /* 客户评价卡片 */
    .testimonial-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      position: relative;
    }
    .rating-stars {
      color: #f59e0b;
      font-size: 1.1rem;
      margin-bottom: 12px;
    }
    .testimonial-text {
      font-size: 0.925rem;
      color: var(--text-sub);
      line-height: 1.65;
      margin-bottom: 16px;
    }
    .client-info {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .client-avatar-text {
      width: 42px;
      height: 42px;
      border-radius: 50%;
      background: var(--primary-light);
      color: var(--primary-color);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1rem;
    }
    .client-name {
      font-size: 0.95rem;
      font-weight: 700;
      color: var(--text-main);
    }
    .client-role {
      font-size: 0.8rem;
      color: var(--text-muted);
    }

    /* FAQ 折叠 */
    .faq-container {
      max-width: 900px;
      margin: 0 auto;
    }
    .faq-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      margin-bottom: 12px;
      overflow: hidden;
      transition: var(--transition);
    }
    .faq-item.active {
      border-color: var(--border-focus);
      box-shadow: var(--shadow-sm);
    }
    .faq-question {
      padding: 18px 24px;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-size: 1.05rem;
      font-weight: 600;
      color: var(--text-main);
      user-select: none;
    }
    .faq-question:hover {
      color: var(--primary-color);
    }
    .faq-icon {
      font-size: 1.25rem;
      transition: transform 0.25s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--primary-color);
    }
    .faq-answer {
      display: none;
      padding: 0 24px 20px;
      color: var(--text-sub);
      font-size: 0.95rem;
      line-height: 1.7;
      border-top: 1px solid #f8fafc;
    }
    .faq-item.active .faq-answer {
      display: block;
    }

    /* 需求表单与联系 */
    .contact-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 36px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-lg);
      padding: 40px;
      box-shadow: var(--shadow-md);
    }
    .form-group {
      margin-bottom: 18px;
    }
    .form-label {
      display: block;
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-main);
      margin-bottom: 6px;
    }
    .form-control {
      width: 100%;
      padding: 11px 14px;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      font-size: 0.95rem;
      color: var(--text-main);
      outline: none;
      transition: var(--transition);
      background-color: #ffffff;
    }
    .form-control:focus {
      border-color: var(--primary-color);
      box-shadow: 0 0 0 3px rgba(26, 86, 219, 0.12);
    }
    textarea.form-control {
      resize: vertical;
      min-height: 110px;
    }
    .contact-info-panel {
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      padding-left: 20px;
      border-left: 1px solid var(--border-color);
    }
    .contact-details h3 {
      font-size: 1.35rem;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 16px;
    }
    .contact-list {
      list-style: none;
      margin-bottom: 24px;
    }
    .contact-list li {
      font-size: 0.95rem;
      color: var(--text-sub);
      margin-bottom: 12px;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .qr-box {
      background: var(--bg-main);
      padding: 16px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      display: inline-block;
      text-align: center;
      max-width: 180px;
    }
    .qr-box img {
      width: 100%;
      height: auto;
      border-radius: var(--radius-sm);
      display: block;
      margin-bottom: 8px;
    }
    .qr-box p {
      font-size: 0.85rem;
      font-weight: 600;
      color: var(--text-main);
    }

    /* 资讯与百科 */
    .article-list {
      list-style: none;
    }
    .article-item {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 14px 18px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-sm);
      margin-bottom: 10px;
      transition: var(--transition);
    }
    .article-item:hover {
      border-color: var(--primary-color);
      background-color: var(--primary-light);
    }
    .article-item a {
      font-size: 0.95rem;
      color: var(--text-main);
      font-weight: 500;
    }
    .article-item span {
      font-size: 0.85rem;
      color: var(--text-muted);
    }

    /* 页脚 */
    .site-footer {
      background-color: #ffffff;
      border-top: 1px solid var(--border-color);
      padding: 50px 0 24px;
      color: var(--text-sub);
    }
    .footer-top {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 32px;
      margin-bottom: 40px;
    }
    .footer-col h4 {
      font-size: 1rem;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 16px;
    }
    .footer-links-list {
      list-style: none;
    }
    .footer-links-list li {
      margin-bottom: 10px;
    }
    .footer-links-list a {
      color: var(--text-sub);
      font-size: 0.9rem;
    }
    .footer-links-list a:hover {
      color: var(--primary-color);
    }
    .friend-links {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 10px;
    }
    .friend-links a {
      font-size: 0.875rem;
      color: var(--text-muted);
      background: var(--bg-alt);
      padding: 4px 10px;
      border-radius: 4px;
    }
    .friend-links a:hover {
      color: var(--primary-color);
      background: var(--primary-light);
    }
    .footer-bottom {
      border-top: 1px solid var(--border-color);
      padding-top: 20px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 16px;
      font-size: 0.875rem;
      color: var(--text-muted);
    }

    /* 浮动客服挂件 */
    .floating-widget {
      position: fixed;
      right: 20px;
      bottom: 30px;
      z-index: 990;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .widget-btn {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background-color: var(--primary-color);
      color: #ffffff;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: var(--shadow-md);
      cursor: pointer;
      border: none;
      transition: var(--transition);
      font-size: 1.15rem;
    }
    .widget-btn:hover {
      background-color: var(--primary-hover);
      transform: scale(1.08);
    }
    #backToTop {
      display: none;
      background-color: #ffffff;
      color: var(--text-main);
      border: 1px solid var(--border-color);
    }
    #backToTop:hover {
      background-color: var(--bg-alt);
    }

    /* 响应式适配 */
    @media (max-width: 992px) {
      .hero-title {
        font-size: 2.1rem;
      }
      .hero-stats {
        grid-template-columns: repeat(2, 1fr);
      }
      .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
      .about-layout {
        grid-template-columns: 1fr;
      }
      .process-timeline {
        grid-template-columns: repeat(2, 1fr);
      }
      .contact-layout {
        grid-template-columns: 1fr;
      }
      .contact-info-panel {
        padding-left: 0;
        border-left: none;
        border-top: 1px solid var(--border-color);
        padding-top: 24px;
      }
      .footer-top {
        grid-template-columns: 1fr 1fr;
      }
      .gallery-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      .menu-toggle {
        display: block;
      }
      .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background-color: #ffffff;
        flex-direction: column;
        padding: 16px 20px;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-md);
      }
      .nav-links.show {
        display: flex;
      }
      .nav-links li {
        width: 100%;
      }
      .nav-links li a {
        padding: 12px 16px;
      }
      .hero-title {
        font-size: 1.75rem;
      }
      .hero-stats {
        grid-template-columns: 1fr;
      }
      .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
      .process-timeline {
        grid-template-columns: 1fr;
      }
      .footer-top {
        grid-template-columns: 1fr;
      }
      .gallery-grid {
        grid-template-columns: 1fr;
      }
    }