/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary: #4E6EF2;
      --primary-dark: #3B54D4;
      --primary-light: #EEF1FE;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --card: #FFFFFF;
      --text: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --shadow-card: 0 2px 12px rgba(31, 35, 41, 0.06);
      --shadow-hover: 0 6px 20px rgba(31, 35, 41, 0.1);
      --radius-md: 12px;
      --radius-btn: 50px;
      --max-width: 1200px;
      --nav-height: 64px;
      --transition: 200ms ease;
      --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }
    h1, h2, h3, h4 {
      font-weight: 600;
      line-height: 1.3;
    }
    h1 {
      font-size: 36px;
      font-weight: 700;
    }
    h2 {
      font-size: 28px;
      font-weight: 600;
    }
    h3 {
      font-size: 20px;
      font-weight: 600;
    }
    .text-secondary {
      color: var(--text-secondary);
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: var(--card);
      border-bottom: 1px solid var(--border-light);
      z-index: 1000;
      display: flex;
      align-items: center;
      box-shadow: 0 1px 4px rgba(0,0,0,0.02);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.5px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text);
      transition: color var(--transition);
      white-space: nowrap;
    }
    .nav-links a:hover, .nav-links a.active {
      color: var(--primary);
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--text);
      cursor: pointer;
      padding: 8px;
    }
    .mobile-menu {
      display: none;
    }
    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: background var(--transition), transform var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 1.5px solid var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: background var(--transition), color var(--transition);
      white-space: nowrap;
    }
    .btn-outline:hover {
      background: var(--primary-light);
    }
    .btn-white {
      background: white;
      color: var(--primary);
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      box-shadow: 0 4px 10px rgba(0,0,0,0.08);
      transition: background var(--transition);
    }
    .btn-white:hover {
      background: #f0f2ff;
    }
    /* 板块通用 */
    section {
      padding: 100px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 56px;
    }
    .section-title h2 {
      margin-bottom: 12px;
      color: var(--text);
    }
    .section-title p {
      color: var(--text-secondary);
      font-size: 18px;
    }
    /* Hero */
    .hero {
      padding: calc(var(--nav-height) + 60px) 0 80px;
      background: var(--bg);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      margin-bottom: 20px;
    }
    .hero-content .subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      line-height: 1.6;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      display: flex;
      justify-content: center;
    }
    .hero-image img {
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      max-height: 420px;
      object-fit: cover;
      width: 100%;
    }
    /* 亮点卡片 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--card);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: transform var(--transition), box-shadow var(--transition);
      text-align: center;
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .feature-icon {
      font-size: 36px;
      color: var(--primary);
      margin-bottom: 20px;
      display: inline-block;
    }
    .feature-card h3 {
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-secondary);
      font-size: 15px;
    }
    /* 服务瀑布流 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--card);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .service-img {
      position: relative;
      overflow: hidden;
      aspect-ratio: 16/9;
    }
    .service-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.3s ease;
    }
    .service-card:hover .service-img img {
      transform: scale(1.05);
    }
    .service-body {
      padding: 20px;
    }
    .service-body h3 {
      margin-bottom: 8px;
    }
    .service-body p {
      color: var(--text-secondary);
      font-size: 15px;
      margin-bottom: 16px;
    }
    .tags {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
    }
    .tag {
      background: var(--primary-light);
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 500;
    }
    /* 方案对比 */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      align-items: start;
    }
    .pricing-card {
      background: var(--card);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      position: relative;
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .pricing-card.recommended {
      border: 2px solid var(--primary);
      transform: scale(1.02);
      box-shadow: var(--shadow-hover);
    }
    .badge {
      position: absolute;
      top: -12px;
      right: 20px;
      background: var(--orange);
      color: white;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
    }
    .pricing-card h3 {
      margin-bottom: 12px;
    }
    .price-desc {
      color: var(--text-secondary);
      margin-bottom: 24px;
      font-size: 15px;
    }
    .feature-list {
      list-style: none;
      margin-bottom: 32px;
      flex: 1;
    }
    .feature-list li {
      margin-bottom: 12px;
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 15px;
    }
    .feature-list i {
      color: var(--primary);
      font-size: 18px;
    }
    .feature-list i.disabled {
      color: #ccc;
    }
    .pricing-card .btn {
      width: 100%;
      justify-content: center;
    }
    /* 数据案例 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .stat-item h3 {
      font-size: 40px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 8px;
    }
    .stat-item p {
      color: var(--text-secondary);
    }
    .logo-wall {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 40px;
      margin-top: 40px;
    }
    .logo-item {
      background: var(--card);
      padding: 20px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      color: var(--text-secondary);
      box-shadow: var(--shadow-card);
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--card);
      border-radius: var(--radius-md);
      margin-bottom: 12px;
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      cursor: pointer;
      user-select: none;
    }
    .faq-question i {
      transition: transform 0.2s;
      color: var(--primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.2s;
      background: #F8F9FC;
      padding: 0 24px;
      color: var(--text-secondary);
      font-size: 15px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 16px 24px;
    }
    .faq-item.active .faq-question i {
      transform: rotate(180deg);
    }
    /* CTA 横幅 */
    .cta-banner {
      background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
      padding: 80px 0;
      text-align: center;
    }
    .cta-banner h2 {
      color: white;
      font-size: 32px;
      margin-bottom: 16px;
    }
    .cta-banner p {
      color: rgba(255,255,255,0.8);
      font-size: 18px;
      margin-bottom: 32px;
    }
    /* 页脚 */
    .footer {
      background: #1F2329;
      color: #86909C;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-col h4 {
      color: white;
      margin-bottom: 20px;
      font-size: 16px;
    }
    .footer-col p, .footer-col a {
      font-size: 14px;
      color: #86909C;
      margin-bottom: 8px;
      display: block;
    }
    .footer-col a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #2E3238;
      padding-top: 24px;
      text-align: center;
      font-size: 14px;
      color: #6B7280;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .hero-grid { flex-direction: column; }
      .features-grid, .services-grid, .pricing-grid { grid-template-columns: repeat(2, 1fr); }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      h1 { font-size: 28px; } h2 { font-size: 22px; } h3 { font-size: 18px; }
      section { padding: 70px 0; }
      .nav-links { display: none; }
      .hamburger { display: block; }
      .mobile-menu {
        display: none;
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 24px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05);
        z-index: 999;
      }
      .mobile-menu.open { display: flex; }
      .mobile-menu a {
        padding: 16px 0;
        border-bottom: 1px solid var(--border-light);
        font-weight: 500;
      }
      .features-grid, .services-grid, .pricing-grid { grid-template-columns: 1fr; }
      .hero-buttons { flex-direction: column; align-items: flex-start; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
    }