/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-light: rgba(78,110,242,0.1);
      --primary-dark: #3A54C4;
      --secondary: #00B578;
      --warning: #FF9F0A;
      --danger: #FA5151;
      --bg: #F5F6FA;
      --white: #FFFFFF;
      --light-blue-bg: #F0F2FF;
      --text-main: #1F2329;
      --text-secondary: #4E5969;
      --text-muted: #86909C;
      --border-light: #E5E8EF;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.10);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 4px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      --transition: 200ms ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      transition: box-shadow var(--transition);
    }
    .header.scrolled {
      box-shadow: var(--shadow-sm);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 68px;
      flex-wrap: wrap;
    }
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-main);
      display: flex;
      align-items: center;
      gap: 6px;
      text-decoration: none;
    }
    .logo i {
      color: var(--primary);
      font-size: 24px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      text-decoration: none;
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 15px;
      transition: color var(--transition);
      white-space: nowrap;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      transition: background var(--transition), box-shadow var(--transition);
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 4px 14px rgba(78,110,242,0.3);
    }
    .btn-primary:focus-visible {
      box-shadow: 0 0 0 3px rgba(78,110,242,0.25);
      outline: none;
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: all var(--transition);
    }
    .btn-outline:hover {
      background: var(--primary-light);
      border-color: var(--primary-dark);
      color: var(--primary-dark);
    }
    .btn-white {
      background: white;
      color: var(--primary);
      border: none;
      padding: 12px 32px;
      font-weight: 700;
      border-radius: var(--radius-btn);
      transition: opacity var(--transition);
    }
    .btn-white:hover {
      opacity: 0.9;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 26px;
      color: var(--text-main);
      cursor: pointer;
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: 68px;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        box-shadow: var(--shadow-md);
        border-top: 1px solid var(--border-light);
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: block;
      }
    }
    /* 通用板块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      font-size: 28px;
      font-weight: 600;
      margin-bottom: 16px;
      color: var(--text-main);
      line-height: 1.4;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 48px;
    }
    /* Hero */
    .hero {
      background: var(--bg);
      display: flex;
      align-items: center;
      min-height: 85vh;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
      flex-wrap: wrap;
    }
    .hero-text {
      flex: 1 1 55%;
    }
    .hero-text h1 {
      font-size: 40px;
      font-weight: 700;
      line-height: 1.3;
      margin-bottom: 20px;
      color: var(--text-main);
    }
    .hero-text .sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      align-items: center;
      gap: 24px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1 1 40%;
      text-align: center;
    }
    .hero-image img {
      max-width: 100%;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-md);
    }
    .text-link {
      color: var(--primary);
      font-weight: 600;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }
    .text-link i {
      font-size: 14px;
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-text h1 {
        font-size: 32px;
      }
    }
    /* 优势卡片 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
      text-align: center;
    }
    .card:hover {
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
    }
    .card i {
      font-size: 40px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .card p {
      font-size: 14px;
      color: var(--text-secondary);
    }
    /* 服务交替 */
    .service-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 80px;
    }
    .service-row.reverse {
      flex-direction: row-reverse;
    }
    .service-img, .service-content {
      flex: 1;
    }
    .service-img img {
      width: 100%;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
    }
    .service-content h3 {
      font-size: 24px;
      margin-bottom: 16px;
    }
    .service-content p {
      color: var(--text-secondary);
      margin-bottom: 24px;
    }
    @media (max-width: 768px) {
      .service-row, .service-row.reverse {
        flex-direction: column;
        text-align: center;
      }
      .cards-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 数据区 */
    .stats {
      background: var(--light-blue-bg);
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      text-align: center;
      gap: 24px;
    }
    .stat-number {
      font-size: 32px;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      font-size: 14px;
      color: var(--text-secondary);
    }
    @media (max-width: 768px) {
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    /* 案例瀑布流 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
    }
    .case-card:hover {
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
    }
    .case-card img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
      transition: transform 0.3s;
    }
    .case-card:hover img {
      transform: scale(1.03);
    }
    .case-info {
      padding: 16px;
    }
    .case-info h3 {
      font-size: 18px;
      margin-bottom: 8px;
    }
    .case-tag {
      background: var(--light-blue-bg);
      color: var(--primary);
      padding: 2px 10px;
      border-radius: var(--radius-tag);
      font-size: 12px;
      display: inline-block;
      margin-top: 8px;
    }
    @media (max-width: 768px) {
      .cases-grid {
        grid-template-columns: 1fr;
      }
    }
    /* FAQ */
    .faq-container {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: white;
      border-radius: var(--radius-btn);
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
    }
    .faq-question {
      padding: 20px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-main);
      transition: color var(--transition);
    }
    .faq-question i {
      transition: transform 0.25s ease;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding: 0 20px;
      color: var(--text-secondary);
    }
    .faq-item.active .faq-question {
      color: var(--primary);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 0 20px 20px;
      border-top: 1px solid var(--border-light);
    }
    /* CTA */
    .cta-block {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 70px 0;
    }
    .cta-block h2 {
      font-size: 32px;
      margin-bottom: 16px;
    }
    .small-note {
      margin-top: 16px;
      font-size: 14px;
      opacity: 0.8;
    }
    /* 页脚 */
    .footer {
      background: #1F2329;
      color: var(--text-muted);
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 16px;
      font-size: 14px;
    }
    .footer a {
      color: var(--text-muted);
      text-decoration: none;
      font-size: 14px;
      display: block;
      margin-bottom: 8px;
    }
    .footer a:hover {
      color: var(--primary);
    }
    .copyright {
      text-align: center;
      margin-top: 32px;
      font-size: 12px;
      border-top: 1px solid #2E3238;
      padding-top: 24px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }