/* roulang page: index */
:root {
      --primary: #1DB954;
      --primary-dark: #17A34A;
      --primary-light: rgba(29, 185, 84, 0.08);
      --secondary: #0A0E27;
      --accent-blue: #4F46E5;
      --bg-light: #F7F9FC;
      --white: #FFFFFF;
      --text-dark: #1F2329;
      --text-muted: #6B7280;
      --text-light: #E5E7EB;
      --warning: #FF6B35;
      --data-highlight: #F59E0B;
      --border-light: rgba(0,0,0,0.05);
      --radius-lg: 24px;
      --radius-md: 16px;
      --radius-sm: 12px;
      --radius-pill: 50px;
      --shadow-card: 0 8px 30px rgba(0,0,0,0.05);
      --shadow-hover: 0 12px 40px rgba(0,0,0,0.1);
      --transition: all 0.25s ease;
      --container-max: 1200px;
      --space-section: 100px;
      --font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-family);
      background-color: var(--bg-light);
      color: var(--text-dark);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: transparent;
    }
    /* 导航栏 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 3px rgba(0,0,0,0.03);
      z-index: 1000;
      height: 72px;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 22px;
      color: var(--secondary);
    }
    .logo-icon {
      font-size: 28px;
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-dark);
      padding: 6px 0;
      border-bottom: 2px solid transparent;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .mobile-toggle {
      display: none;
      font-size: 26px;
      color: var(--secondary);
    }
    /* 移动端底部导航 */
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(20px);
      border-top: 1px solid rgba(0,0,0,0.04);
      padding: 8px 16px;
      display: none;
      justify-content: space-around;
      z-index: 999;
    }
    .mobile-bottom-nav a {
      display: flex;
      flex-direction: column;
      align-items: center;
      font-size: 12px;
      color: var(--text-muted);
      gap: 4px;
      transition: var(--transition);
    }
    .mobile-bottom-nav a i {
      font-size: 20px;
    }
    .mobile-bottom-nav a.active {
      color: var(--primary);
    }
    /* Hero */
    #hero {
      padding: 140px 0 100px;
      background: var(--white);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 48px;
      line-height: 1.2;
      font-weight: 700;
      margin-bottom: 20px;
      color: var(--secondary);
    }
    .hero-content .highlight {
      color: var(--primary);
    }
    .hero-content p {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 16px;
      transition: var(--transition);
      box-shadow: 0 8px 18px rgba(29,185,132,0.3);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 12px 24px rgba(29,185,132,0.4);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 36px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 16px;
      transition: var(--transition);
    }
    .btn-secondary:hover {
      background: var(--primary-light);
    }
    .hero-image img {
      width: 100%;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.08);
      aspect-ratio: 4/3;
      object-fit: cover;
    }
    /* 通用板块 */
    section {
      padding: var(--space-section) 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 56px;
    }
    .section-title h2 {
      font-size: 36px;
      font-weight: 700;
      color: var(--secondary);
    }
    .section-title p {
      font-size: 18px;
      color: var(--text-muted);
      margin-top: 12px;
    }
    /* 核心优势 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .feature-card {
      background: var(--white);
      padding: 40px 28px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      text-align: center;
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .feature-icon {
      width: 72px;
      height: 72px;
      background: var(--primary-light);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 24px;
      color: var(--primary);
      font-size: 32px;
    }
    .feature-card h4 {
      font-size: 22px;
      margin-bottom: 14px;
    }
    /* 产品服务 */
    .service-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .service-image img {
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
    }
    .service-list {
      list-style: none;
      margin-top: 24px;
    }
    .service-list li {
      display: flex;
      align-items: flex-start;
      gap: 16px;
      margin-bottom: 24px;
      font-size: 18px;
    }
    .service-dot {
      width: 12px;
      height: 12px;
      background: var(--primary);
      border-radius: 50%;
      margin-top: 8px;
      flex-shrink: 0;
    }
    /* 数据深色区 */
    #data {
      background: var(--secondary);
      color: white;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
      text-align: center;
    }
    .stat-card {
      background: rgba(255,255,255,0.08);
      backdrop-filter: blur(8px);
      padding: 36px 16px;
      border-radius: var(--radius-md);
      border: 1px solid rgba(255,255,255,0.1);
    }
    .stat-number {
      font-size: 44px;
      font-weight: 700;
      color: var(--primary);
      margin-bottom: 8px;
    }
    .stat-label {
      font-size: 16px;
      color: var(--text-light);
    }
    /* 案例 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .case-card {
      background: var(--white);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .case-card:hover {
      transform: translateY(-4px);
    }
    .case-img {
      aspect-ratio: 16/9;
      object-fit: cover;
      width: 100%;
    }
    .case-info {
      padding: 20px;
    }
    .case-tag {
      background: var(--primary-light);
      color: var(--primary-dark);
      padding: 4px 16px;
      border-radius: 50px;
      font-size: 13px;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 8px;
    }
    /* 解决方案时间轴 */
    .solution-steps {
      display: flex;
      flex-direction: column;
      gap: 32px;
      position: relative;
      padding-left: 40px;
    }
    .solution-steps::before {
      content: '';
      position: absolute;
      left: 16px;
      top: 8px;
      bottom: 8px;
      width: 2px;
      background: #E5E7EB;
    }
    .step-item {
      display: flex;
      gap: 28px;
      align-items: flex-start;
    }
    .step-marker {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: bold;
      position: relative;
      z-index: 2;
      flex-shrink: 0;
    }
    .step-card {
      background: var(--white);
      padding: 24px;
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      flex: 1;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: var(--white);
      border-radius: var(--radius-sm);
      box-shadow: 0 2px 12px rgba(0,0,0,0.02);
      overflow: hidden;
    }
    .faq-question {
      padding: 22px 28px;
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: transparent;
      width: 100%;
      text-align: left;
    }
    .faq-answer {
      padding: 0 28px 22px;
      color: var(--text-muted);
      display: none;
    }
    .faq-item.open .faq-answer {
      display: block;
    }
    .faq-icon {
      font-size: 22px;
      color: var(--primary);
    }
    /* CTA */
    #cta {
      background: linear-gradient(135deg, #1DB954 0%, #17A34A 100%);
      color: white;
      text-align: center;
    }
    .cta-content h2 {
      font-size: 38px;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .cta-btn {
      background: white;
      color: #065F46;
      padding: 16px 48px;
      border-radius: 50px;
      font-weight: 700;
      font-size: 18px;
      margin-top: 32px;
      display: inline-block;
    }
    /* 页脚 */
    footer {
      background: var(--secondary);
      color: var(--text-light);
      padding: 70px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: white;
      margin-bottom: 16px;
    }
    .footer-desc {
      color: #9CA3AF;
    }
    .footer-links h4 {
      color: white;
      margin-bottom: 20px;
    }
    .footer-links a {
      display: block;
      color: #9CA3AF;
      margin-bottom: 12px;
    }
    .footer-links a:hover {
      color: var(--primary);
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
      text-align: center;
      color: #9CA3AF;
    }
    @media (max-width: 1024px) {
      .hero-grid, .service-grid {
        grid-template-columns: 1fr;
      }
      .features-grid, .cases-grid {
        grid-template-columns: repeat(2,1fr);
      }
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
      .nav-links {
        display: none;
      }
      .mobile-toggle {
        display: block;
      }
      .mobile-bottom-nav {
        display: flex;
      }
      .header {
        height: 64px;
      }
      #hero {
        padding: 100px 0 60px;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .features-grid, .cases-grid, .stats-grid, .footer-grid {
        grid-template-columns: 1fr;
      }
      .section-title h2 {
        font-size: 28px;
      }
      .btn-group {
        flex-direction: column;
      }
      .solution-steps {
        padding-left: 30px;
      }
    }
    @media (max-width: 520px) {
      .hero-content h1 {
        font-size: 28px;
      }
    }