/* 基础重置与炫彩荧光浅色主题 */
    :root {
      --bg-main: #f8fafc;
      --bg-card: #ffffff;
      --bg-glass: rgba(255, 255, 255, 0.85);
      --text-main: #0f172a;
      --text-muted: #475569;
      --primary: #6366f1;
      --primary-hover: #4f46e5;
      --neon-cyan: #06b6d4;
      --neon-pink: #ec4899;
      --neon-green: #10b981;
      --border-color: rgba(99, 102, 241, 0.15);
      --shadow-glow: 0 10px 30px -10px rgba(99, 102, 241, 0.2);
      --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;
      background-color: var(--bg-main);
      color: var(--text-main);
      line-height: 1.6;
    }

    body {
      overflow-x: hidden;
      min-height: 100vh;
      display: flex;
      flex-direction: column;
    }

    a {
      color: var(--primary);
      text-decoration: none;
      transition: all 0.2s ease;
    }

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

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

    .section {
      padding: 70px 0;
      position: relative;
    }

    .section-header {
      text-align: center;
      margin-bottom: 45px;
    }

    .section-tag {
      display: inline-block;
      padding: 4px 14px;
      border-radius: 20px;
      background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(6, 182, 212, 0.1));
      color: var(--primary);
      font-size: 0.85rem;
      font-weight: 600;
      border: 1px solid var(--border-color);
      margin-bottom: 12px;
    }

    .section-title {
      font-size: 2.2rem;
      font-weight: 800;
      color: var(--text-main);
      letter-spacing: -0.5px;
    }

    .section-desc {
      color: var(--text-muted);
      font-size: 1rem;
      margin-top: 10px;
      max-width: 650px;
      margin-left: auto;
      margin-right: auto;
    }

    /* 顶部导航 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background: rgba(255, 255, 255, 0.9);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-color);
    }

    .nav-wrapper {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
    }

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

    .ai-page-logo {
      height: 38px;
      width: auto;
      display: block;
    }

    .brand-title {
      font-size: 1.25rem;
      font-weight: 800;
      background: linear-gradient(135deg, var(--primary), var(--neon-cyan));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 0; /* 严格按照规则要求 gap 为 0 */
      list-style: none;
    }

    .nav-links li a {
      padding: 8px 12px;
      font-size: 0.92rem;
      font-weight: 500;
      color: var(--text-main);
      display: block;
    }

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

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

    .btn-neon {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 22px;
      border-radius: 8px;
      font-weight: 600;
      font-size: 0.95rem;
      background: linear-gradient(135deg, var(--primary), var(--neon-cyan));
      color: #ffffff !important;
      box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
      border: none;
      cursor: pointer;
      transition: transform 0.2s ease, box-shadow 0.2s ease;
    }

    .btn-neon:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
    }

    .btn-outline {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 9px 20px;
      border-radius: 8px;
      font-weight: 600;
      font-size: 0.95rem;
      border: 1.5px solid var(--primary);
      color: var(--primary) !important;
      background: transparent;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .btn-outline:hover {
      background: rgba(99, 102, 241, 0.08);
    }

    /* 移动端菜单按钮 */
    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 1.5rem;
      color: var(--text-main);
      cursor: pointer;
    }

    /* 1. 首屏 Hero 区域 (严格无图片) */
    .hero-section {
      padding: 90px 0 70px;
      background: radial-gradient(circle at 50% 20%, rgba(99, 102, 241, 0.08) 0%, rgba(6, 182, 212, 0.03) 50%, transparent 80%);
      text-align: center;
    }

    .hero-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      padding: 6px 16px;
      border-radius: 30px;
      background: rgba(255, 255, 255, 0.9);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-glow);
      font-size: 0.88rem;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 24px;
    }

    .hero-title {
      font-size: 2.8rem;
      font-weight: 900;
      line-height: 1.25;
      margin-bottom: 20px;
      letter-spacing: -0.8px;
      color: var(--text-main);
    }

    .hero-title span {
      background: linear-gradient(135deg, var(--primary), var(--neon-cyan), var(--neon-pink));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-subtitle {
      font-size: 1.15rem;
      color: var(--text-muted);
      max-width: 780px;
      margin: 0 auto 36px;
      line-height: 1.7;
    }

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

    .hero-metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 20px;
      max-width: 960px;
      margin: 0 auto;
    }

    .metric-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 22px 16px;
      border-radius: var(--radius);
      box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
      text-align: center;
      transition: transform 0.2s;
    }

    .metric-card:hover {
      transform: translateY(-4px);
    }

    .metric-num {
      font-size: 2rem;
      font-weight: 800;
      color: var(--primary);
      line-height: 1.1;
      margin-bottom: 6px;
    }

    .metric-label {
      font-size: 0.88rem;
      color: var(--text-muted);
    }

    /* 通用卡片网格 */
    .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);
      padding: 30px;
      border-radius: var(--radius);
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
    }

    .feature-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-glow);
      border-color: rgba(99, 102, 241, 0.3);
    }

    .card-icon {
      width: 48px;
      height: 48px;
      border-radius: 10px;
      background: linear-gradient(135deg, rgba(99, 102, 241, 0.12), rgba(6, 182, 212, 0.12));
      color: var(--primary);
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.4rem;
      margin-bottom: 18px;
      font-weight: bold;
    }

    .card-title {
      font-size: 1.2rem;
      font-weight: 700;
      margin-bottom: 10px;
      color: var(--text-main);
    }

    .card-text {
      font-size: 0.93rem;
      color: var(--text-muted);
      line-height: 1.6;
    }

    /* 流程步骤 */
    .process-grid {
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      gap: 16px;
    }

    .process-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 24px 16px;
      border-radius: var(--radius);
      position: relative;
      text-align: center;
    }

    .process-num {
      width: 32px;
      height: 32px;
      background: var(--primary);
      color: #fff;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 12px;
      font-weight: 700;
      font-size: 0.9rem;
    }

    /* 模型列表标签 */
    .model-tags {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      justify-content: center;
      margin-top: 25px;
    }

    .model-tag-item {
      padding: 8px 16px;
      border-radius: 6px;
      background: #ffffff;
      border: 1px solid var(--border-color);
      font-size: 0.9rem;
      font-weight: 600;
      color: var(--text-main);
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.02);
      transition: all 0.2s;
    }

    .model-tag-item:hover {
      border-color: var(--primary);
      color: var(--primary);
    }

    /* 案例展示区 */
    .case-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: 0 4px 15px rgba(0, 0, 0, 0.03);
    }

    .case-img-box {
      width: 100%;
      overflow: hidden;
      background: #f1f5f9;
    }

    .case-img-box img {
      width: 100%;
      height: 220px;
      object-fit: cover;
      display: block;
      transition: transform 0.3s;
    }

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

    .case-info {
      padding: 20px;
    }

    /* 对比表格 */
    .table-container {
      overflow-x: auto;
      background: var(--bg-card);
      border-radius: var(--radius);
      border: 1px solid var(--border-color);
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.02);
    }

    .compare-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
      min-width: 680px;
    }

    .compare-table th,
    .compare-table td {
      padding: 16px 20px;
      border-bottom: 1px solid rgba(99, 102, 241, 0.08);
    }

    .compare-table th {
      background: rgba(99, 102, 241, 0.04);
      font-weight: 700;
      color: var(--text-main);
    }

    .compare-table tr:hover {
      background: rgba(99, 102, 241, 0.02);
    }

    .badge-recommend {
      background: #10b981;
      color: #fff;
      padding: 3px 10px;
      border-radius: 12px;
      font-size: 0.8rem;
    }

    /* FAQ 折叠面板 */
    .faq-list {
      max-width: 860px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 14px;
    }

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

    .faq-header {
      padding: 18px 24px;
      font-weight: 700;
      font-size: 1.05rem;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: space-between;
      user-select: none;
      color: var(--text-main);
    }

    .faq-content {
      padding: 0 24px 18px;
      color: var(--text-muted);
      font-size: 0.95rem;
      display: none;
      line-height: 1.7;
    }

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

    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }

    .faq-icon {
      transition: transform 0.2s;
    }

    /* 评论卡片 */
    .review-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 24px;
      border-radius: var(--radius);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .review-user {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-top: 16px;
    }

    .avatar-placeholder {
      width: 42px;
      height: 42px;
      border-radius: 50%;
      background: linear-gradient(135deg, var(--primary), var(--neon-cyan));
      color: #fff;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
    }

    /* 文章列表 */
    .article-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
    }

    .article-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 20px;
      border-radius: var(--radius);
    }

    .article-card h3 {
      font-size: 1.05rem;
      margin-bottom: 10px;
    }

    /* 表单与联系 */
    .contact-wrapper {
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 40px;
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      padding: 40px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-glow);
    }

    .contact-form {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .form-group {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    .form-group label {
      font-size: 0.9rem;
      font-weight: 600;
    }

    .form-control {
      width: 100%;
      padding: 12px 14px;
      border-radius: 8px;
      border: 1px solid var(--border-color);
      background: #f8fafc;
      font-size: 0.95rem;
      color: var(--text-main);
      outline: none;
    }

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

    /* 页脚与系统底部 */
    .site-footer {
      background: #0f172a;
      color: #94a3b8;
      padding: 60px 0 30px;
      margin-top: auto;
    }

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

    .footer-col h4 {
      color: #f8fafc;
      margin-bottom: 18px;
      font-size: 1.1rem;
    }

    .footer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

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

    .footer-links a:hover {
      color: #ffffff;
    }

    .friendship-links {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
    }

    .friendship-links a {
      color: #94a3b8;
      font-size: 0.9rem;
    }

    .friendship-links a:hover {
      color: var(--neon-cyan);
    }

    .footer-bottom {
      border-top: 1px solid rgba(255, 255, 255, 0.1);
      padding-top: 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 0.88rem;
    }

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

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

    /* 响应式样式 */
    @media (max-width: 992px) {
      .hero-title { font-size: 2.2rem; }
      .grid-4, .process-grid { grid-template-columns: repeat(2, 1fr); }
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .contact-wrapper { grid-template-columns: 1fr; }
      .hero-metrics-grid { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: #ffffff;
        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;
      }

      .mobile-toggle {
        display: block;
      }

      .grid-3, .grid-2, .article-grid {
        grid-template-columns: 1fr;
      }

      .hero-title { font-size: 1.8rem; }
      .footer-grid { grid-template-columns: 1fr; }
      .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
    }