/* roulang page: index */
/* CSS 变量与全局重置 */
    :root {
      --primary: #FF6B35;
      --primary-dark: #FF3E1D;
      --accent: #00D2FF;
      --deep-blue: #1A1F36;
      --bg-warm: #F9F8F6;
      --card-bg: #FFFFFF;
      --text-body: #4B5563;
      --text-light: #9CA3AF;
      --border-light: #E5E7EB;
      --shadow-card: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.08);
      --radius-lg: 20px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --transition: all 0.25s ease;
    }
    
    * {
      box-sizing: border-box;
    }
    
    body {
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
      margin: 0;
      padding: 0;
      background-color: var(--bg-warm);
      color: var(--text-body);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
    }
    
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }
    
    h1, h2, h3, h4 {
      color: var(--deep-blue);
      font-weight: 600;
      margin: 0;
    }
    
    h1 {
      font-size: clamp(2.2rem, 6vw, 3.5rem);
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
    }
    
    h2 {
      font-size: clamp(1.8rem, 5vw, 2.5rem);
      line-height: 1.3;
      margin-bottom: 0.75rem;
    }
    
    .section {
      padding: 100px 0;
    }
    
    @media (max-width: 768px) {
      .section {
        padding: 70px 0;
      }
      .container {
        padding: 0 20px;
      }
    }
    
    /* 导航毛玻璃效果 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid transparent;
      transition: var(--transition);
    }
    
    .navbar.scrolled {
      background: rgba(255,255,255,0.95);
      box-shadow: 0 4px 20px rgba(0,0,0,0.05);
      border-bottom: 1px solid var(--border-light);
    }
    
    .nav-link {
      color: var(--deep-blue);
      font-weight: 500;
      transition: color 0.2s;
      text-decoration: none;
    }
    
    .nav-link:hover {
      color: var(--primary);
    }
    
    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--primary-dark));
      color: white;
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-md);
      font-weight: 600;
      transition: var(--transition);
      display: inline-block;
      text-decoration: none;
      box-shadow: 0 6px 18px rgba(255,107,53,0.3);
      cursor: pointer;
    }
    
    .btn-primary:hover {
      filter: brightness(1.08);
      box-shadow: 0 10px 24px rgba(255,107,53,0.4);
      transform: translateY(-1px);
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--deep-blue);
      color: var(--deep-blue);
      padding: 12px 28px;
      border-radius: var(--radius-md);
      font-weight: 600;
      transition: var(--transition);
      display: inline-block;
      text-decoration: none;
    }
    
    .btn-outline:hover {
      background: #E8ECF4;
      border-color: var(--primary);
      color: var(--primary);
    }
    
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      padding: 28px;
      height: 100%;
    }
    
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    
    .badge {
      background: rgba(0,210,255,0.1);
      color: var(--accent);
      font-weight: 600;
      font-size: 0.8rem;
      padding: 4px 12px;
      border-radius: 20px;
      display: inline-block;
      border: 1px solid rgba(0,210,255,0.2);
    }
    
    .data-badge {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.2;
    }
    
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
      cursor: pointer;
      transition: background 0.2s;
    }
    
    .faq-item.active {
      background: #F3F4F6;
      margin: 0 -12px;
      padding-left: 12px;
      padding-right: 12px;
      border-radius: var(--radius-md);
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
    }
    
    .footer-link {
      color: var(--text-light);
      text-decoration: none;
      transition: color 0.2s;
    }
    
    .footer-link:hover {
      color: white;
    }
    
    /* 移动端菜单 */
    .mobile-menu {
      background: rgba(26,31,54,0.95);
      backdrop-filter: blur(16px);
    }