/* roulang page: index */
:root {
      --primary-deep: #0A2540;
      --secondary-green: #00A86B;
      --bg-light-gray: #F8FAFC;
      --card-white: #FFFFFF;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --border-light: #E2E8F0;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.02);
      --shadow-elevated: 0 10px 25px rgba(0,0,0,0.08);
      --radius-lg: 16px;
      --radius-md: 8px;
      --transition-smooth: all 0.25s ease;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-light-gray);
      color: var(--text-main);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      margin: 0;
    }
    
    /* 容器与栅格 */
    .container-custom {
      max-width: 1200px;
      margin: 0 auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    
    /* 导航栏固定效果 */
    .navbar {
      background-color: rgba(255,255,255,0.98);
      backdrop-filter: blur(8px);
      height: 72px;
      transition: box-shadow 0.3s ease;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
    }
    .navbar.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    }
    
    .nav-link {
      color: var(--text-muted);
      font-weight: 500;
      font-size: 0.95rem;
      transition: color 0.2s;
    }
    .nav-link:hover {
      color: var(--primary-deep);
    }
    
    /* 主按钮与次按钮 */
    .btn-primary {
      background-color: var(--primary-deep);
      color: white;
      border-radius: var(--radius-md);
      padding: 12px 28px;
      font-weight: 600;
      border: none;
      cursor: pointer;
      display: inline-block;
      transition: var(--transition-smooth);
      box-shadow: 0 4px 10px rgba(10,37,64,0.15);
      text-decoration: none;
      white-space: nowrap;
    }
    .btn-primary:hover {
      background-color: #14365C;
      transform: translateY(-2px);
      box-shadow: 0 8px 20px rgba(10,37,64,0.25);
      color: white;
    }
    
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary-deep);
      color: var(--primary-deep);
      border-radius: var(--radius-md);
      padding: 11px 28px;
      font-weight: 600;
      display: inline-block;
      transition: var(--transition-smooth);
      text-decoration: none;
      white-space: nowrap;
    }
    .btn-secondary:hover {
      background-color: var(--primary-deep);
      color: white;
    }
    
    /* 各类标题字体 */
    .h1-style {
      font-size: clamp(2rem, 5vw, 3rem);
      font-weight: 800;
      color: var(--primary-deep);
      letter-spacing: -0.02em;
      line-height: 1.3;
    }
    .h2-style {
      font-size: clamp(1.8rem, 4vw, 2.4rem);
      font-weight: 700;
      color: var(--primary-deep);
      text-align: center;
      margin-bottom: 1rem;
    }
    .h3-style {
      font-size: 1.25rem;
      font-weight: 600;
      color: var(--primary-deep);
    }
    
    /* 卡片样式 */
    .card {
      background: var(--card-white);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      padding: 32px;
      transition: var(--transition-smooth);
    }
    .flat-card {
      background: #F1F5F9;
      border-radius: var(--radius-lg);
      padding: 28px;
      box-shadow: none;
    }
    
    /* 数据突出 */
    .data-highlight {
      font-size: 2rem;
      font-weight: 800;
      color: var(--secondary-green);
    }
    
    /* FAQ 手风琴样式 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      color: var(--primary-deep);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    .faq-icon {
      color: var(--secondary-green);
      font-size: 1.2rem;
      transition: transform 0.3s;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    
    /* 证言卡片 */
    .testimonial-card {
      background: #F8FAFC;
      border-radius: var(--radius-lg);
      padding: 32px;
      position: relative;
    }
    .quote-mark {
      font-size: 4rem;
      color: rgba(10,37,64,0.08);
      position: absolute;
      top: 10px;
      left: 20px;
      line-height: 1;
      font-family: serif;
    }
    
    /* 移动端导航 */
    .mobile-menu {
      display: none;
    }
    .drawer {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(255,255,255,0.99);
      backdrop-filter: blur(12px);
      z-index: 100;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      transform: translateY(-100%);
      transition: transform 0.4s cubic-bezier(0.23,1,0.32,1);
    }
    .drawer.open {
      transform: translateY(0);
    }
    
    @media (max-width: 768px) {
      .container-custom {
        padding-left: 20px;
        padding-right: 20px;
      }
      .mobile-menu {
        display: block;
      }
      .desktop-nav-links {
        display: none;
      }
    }
    
    /* 英雄区图片渐变层 */
    .hero-img-overlay {
      background: linear-gradient(90deg, rgba(248,250,252,0.9) 0%, rgba(248,250,252,0.4) 60%);
    }