:root {
      --primary-color: #0284c7;
      --primary-hover: #0369a1;
      --accent-color: #06b6d4;
      --text-main: #0f172a;
      --text-muted: #475569;
      --bg-page: #f8fafc;
      --bg-card: #ffffff;
      --border-color: #e2e8f0;
      --card-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
      --card-shadow-hover: 0 12px 28px -4px rgba(2, 132, 199, 0.12);
      --radius: 12px;
      --max-width: 1200px;
    }

    * {
      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;
      color: var(--text-main);
      background-color: var(--bg-page);
      line-height: 1.6;
    }

    body {
      background: linear-gradient(180deg, #f0f9ff 0%, #f8fafc 400px, #ffffff 100%);
      color: var(--text-main);
      overflow-x: hidden;
    }

    .container {
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }

    /* 顶部导航 */
    header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(8px);
      border-bottom: 1px solid var(--border-color);
    }

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

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

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

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

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

    .nav-links li a {
      text-decoration: none;
      color: var(--text-muted);
      font-weight: 500;
      font-size: 15px;
      padding: 8px 12px;
      transition: color 0.2s, background-color 0.2s;
      border-radius: 6px;
    }

    .nav-links li a:hover,
    .nav-links li a.active {
      color: var(--primary-color);
      background-color: #e0f2fe;
    }

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

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 20px;
      font-size: 15px;
      font-weight: 600;
      border-radius: 8px;
      text-decoration: none;
      cursor: pointer;
      transition: all 0.25s ease;
      border: 1px solid transparent;
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
      color: #ffffff;
      box-shadow: 0 4px 14px rgba(2, 132, 199, 0.3);
    }

    .btn-primary:hover {
      background: linear-gradient(135deg, var(--primary-hover), var(--primary-color));
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(2, 132, 199, 0.4);
    }

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

    .btn-outline:hover {
      background-color: #e0f2fe;
      transform: translateY(-2px);
    }

    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }

    .menu-toggle span {
      display: block;
      width: 24px;
      height: 2px;
      background-color: var(--text-main);
      transition: 0.3s;
    }

    /* 首屏 Hero */
    .hero-section {
      padding: 80px 0 60px;
      text-align: center;
      position: relative;
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      padding: 6px 16px;
      background: #e0f2fe;
      color: var(--primary-color);
      border-radius: 30px;
      font-size: 14px;
      font-weight: 600;
      margin-bottom: 24px;
      border: 1px solid #bae6fd;
    }

    .hero-title {
      font-size: 40px;
      font-weight: 800;
      line-height: 1.3;
      margin-bottom: 20px;
      color: var(--text-main);
    }

    .hero-title span {
      background: linear-gradient(135deg, #0284c7, #06b6d4);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-desc {
      font-size: 18px;
      color: var(--text-muted);
      max-width: 820px;
      margin: 0 auto 36px;
      line-height: 1.8;
    }

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

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

    .stat-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 24px 16px;
      border-radius: var(--radius);
      box-shadow: var(--card-shadow);
      transition: transform 0.25s, box-shadow 0.25s;
    }

    .stat-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--card-shadow-hover);
      border-color: #7dd3fc;
    }

    .stat-number {
      font-size: 32px;
      font-weight: 800;
      color: var(--primary-color);
      margin-bottom: 6px;
    }

    .stat-label {
      font-size: 14px;
      color: var(--text-muted);
      font-weight: 500;
    }

    /* 通用章节样式 */
    section {
      padding: 70px 0;
    }

    .section-header {
      text-align: center;
      margin-bottom: 48px;
    }

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

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

    .section-subtitle {
      font-size: 16px;
      color: var(--text-muted);
      max-width: 680px;
      margin: 0 auto;
    }

    /* 网格卡片 */
    .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;
      align-items: center;
    }

    .card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 28px;
      box-shadow: var(--card-shadow);
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--card-shadow-hover);
      border-color: #38bdf8;
    }

    .card-icon {
      width: 48px;
      height: 48px;
      border-radius: 10px;
      background: #e0f2fe;
      color: var(--primary-color);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 22px;
      font-weight: bold;
      margin-bottom: 18px;
    }

    .card-title {
      font-size: 19px;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text-main);
    }

    .card-text {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.7;
      flex-grow: 1;
    }

    /* 标签云与模型池 */
    .model-tags-container {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
      margin-top: 30px;
    }

    .model-tag {
      background: #ffffff;
      border: 1px solid var(--border-color);
      padding: 8px 16px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 500;
      color: var(--text-main);
      box-shadow: 0 2px 6px rgba(0,0,0,0.02);
      transition: 0.2s;
    }

    .model-tag:hover {
      border-color: var(--primary-color);
      color: var(--primary-color);
      background-color: #f0f9ff;
    }

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

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

    .step-badge {
      position: absolute;
      top: -12px;
      left: 20px;
      background: var(--primary-color);
      color: #fff;
      font-size: 12px;
      font-weight: 700;
      padding: 2px 10px;
      border-radius: 12px;
    }

    .step-title {
      font-size: 17px;
      font-weight: 700;
      margin: 10px 0 8px;
    }

    .step-desc {
      font-size: 13px;
      color: var(--text-muted);
      line-height: 1.6;
    }

    /* 对比表格 */
    .comparison-wrapper {
      overflow-x: auto;
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      box-shadow: var(--card-shadow);
      margin-bottom: 24px;
    }

    .comparison-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
      min-width: 600px;
    }

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

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

    .comparison-table tr:last-child td {
      border-bottom: none;
    }

    .highlight-col {
      background-color: #f0f9ff;
      color: var(--primary-color);
      font-weight: 600;
    }

    .score-banner {
      background: linear-gradient(135deg, #0284c7, #0284c7);
      color: #ffffff;
      padding: 24px;
      border-radius: var(--radius);
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 16px;
    }

    .score-left {
      display: flex;
      align-items: center;
      gap: 16px;
    }

    .score-val {
      font-size: 36px;
      font-weight: 800;
      color: #fef08a;
    }

    /* 案例图片流 */
    .media-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--card-shadow);
    }

    .media-img-box {
      width: 100%;
      aspect-ratio: 16 / 9;
      background: #f1f5f9;
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    }

    .media-img-box.square {
      aspect-ratio: 1 / 1;
    }

    .media-img-box img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.3s ease;
    }

    .media-card:hover .media-img-box img {
      transform: scale(1.04);
    }

    .media-body {
      padding: 18px;
    }

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

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

    /* 用户评论 */
    .testimonial-card {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 24px;
      box-shadow: var(--card-shadow);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .testimonial-text {
      font-size: 14px;
      color: var(--text-muted);
      line-height: 1.7;
      margin-bottom: 16px;
      font-style: italic;
    }

    .testimonial-user {
      display: flex;
      align-items: center;
      gap: 12px;
      border-top: 1px dashed var(--border-color);
      padding-top: 12px;
    }

    .user-avatar-placeholder {
      width: 40px;
      height: 40px;
      border-radius: 50%;
      background: #e0f2fe;
      color: var(--primary-color);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 14px;
    }

    .user-info-name {
      font-size: 14px;
      font-weight: 700;
    }

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

    /* 文章列表 */
    .article-list {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 16px;
    }

    .article-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      padding: 16px 20px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      text-decoration: none;
      color: var(--text-main);
      transition: all 0.2s;
    }

    .article-item:hover {
      border-color: var(--primary-color);
      color: var(--primary-color);
      transform: translateX(4px);
    }

    .article-item span {
      font-size: 14px;
      font-weight: 500;
    }

    /* FAQ 折叠面板 */
    .faq-container {
      max-width: 860px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .faq-item {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow: hidden;
      transition: 0.2s;
    }

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

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

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

    .faq-answer {
      padding: 0 24px;
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      background: #f8fafc;
      color: var(--text-muted);
      font-size: 14px;
      line-height: 1.7;
    }

    .faq-item.active .faq-answer {
      padding: 16px 24px 20px;
      max-height: 300px;
    }

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

    /* 表单与联系模块 */
    .form-container {
      background: #ffffff;
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      padding: 36px;
      box-shadow: var(--card-shadow);
    }

    .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: 12px 14px;
      border: 1px solid var(--border-color);
      border-radius: 8px;
      font-size: 14px;
      color: var(--text-main);
      background-color: #f8fafc;
      transition: border-color 0.2s, background-color 0.2s;
    }

    .form-control:focus {
      outline: none;
      border-color: var(--primary-color);
      background-color: #ffffff;
    }

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

    /* 浮动客服 */
    .floating-contact {
      position: fixed;
      right: 20px;
      bottom: 80px;
      z-index: 999;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .floating-btn {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background: var(--primary-color);
      color: #ffffff;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 4px 12px rgba(0,0,0,0.15);
      cursor: pointer;
      text-decoration: none;
      font-size: 18px;
      position: relative;
    }

    .floating-btn:hover .floating-popup {
      display: block;
    }

    .floating-popup {
      display: none;
      position: absolute;
      right: 56px;
      bottom: 0;
      background: #ffffff;
      border: 1px solid var(--border-color);
      padding: 12px;
      border-radius: 8px;
      box-shadow: 0 8px 24px rgba(0,0,0,0.12);
      width: 160px;
      text-align: center;
    }

    .floating-popup img {
      width: 100%;
      height: auto;
      border-radius: 4px;
      margin-bottom: 6px;
    }

    .floating-popup p {
      font-size: 12px;
      color: var(--text-muted);
      margin: 0;
    }

    /* 友情链接与页脚 */
    footer {
      background: #f1f5f9;
      border-top: 1px solid var(--border-color);
      padding: 50px 0 24px;
      color: var(--text-muted);
      font-size: 14px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
      margin-bottom: 40px;
    }

    .footer-title {
      font-size: 16px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 16px;
    }

    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }

    .footer-links a,
    .friendly-links a {
      color: var(--text-muted);
      text-decoration: none;
      transition: color 0.2s;
    }

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

    .friendly-links-wrap {
      border-top: 1px solid var(--border-color);
      padding: 20px 0;
      margin-bottom: 20px;
    }

    .friendly-links {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
      align-items: center;
    }

    .footer-bottom {
      text-align: center;
      border-top: 1px solid var(--border-color);
      padding-top: 20px;
      font-size: 13px;
    }

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

    @media (max-width: 768px) {
      .menu-toggle {
        display: flex;
      }
      .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: #ffffff;
        border-bottom: 1px solid var(--border-color);
        padding: 16px;
      }
      .nav-links.active {
        display: flex;
      }
      .nav-links li {
        width: 100%;
      }
      .nav-links li a {
        display: block;
        padding: 10px 16px;
      }
      .hero-title {
        font-size: 28px;
      }
      .hero-desc {
        font-size: 15px;
      }
      .grid-3,
      .grid-4,
      .step-grid,
      .hero-stats-grid,
      .article-list {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .form-container {
        padding: 20px;
      }
    }