/* roulang page: index */
:root {
      --primary: #1A5F7A;
      --primary-hover: #154E61;
      --secondary: #0D9488;
      --accent: #F59E0B;
      --accent-hover: #D97706;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --border: #E2E8F0;
      --text-dark: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --white: #FFFFFF;
      --footer-bg: #0F172A;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-hover: 0 10px 25px -5px rgba(0,0,0,0.08), 0 4px 10px -2px rgba(0,0,0,0.05);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-inter: 'Inter', -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }
    
    * {
      box-sizing: border-box;
    }
    
    body {
      font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.7;
      margin: 0;
      padding: 0;
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }
    
    .inter-font {
      font-family: var(--font-inter);
    }
    
    .container-custom {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (max-width: 640px) {
      .container-custom {
        padding-left: 1rem;
        padding-right: 1rem;
      }
    }
    
    /* 导航 */
    .nav-bar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(8px);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      z-index: 50;
      transition: box-shadow 0.25s ease;
    }
    .nav-bar.scrolled {
      box-shadow: 0 4px 12px rgba(0,0,0,0.06);
    }
    
    .nav-link {
      color: var(--text-body);
      font-weight: 500;
      padding: 0.5rem 1rem;
      border-radius: 6px;
      transition: color 0.15s, background-color 0.15s;
      text-decoration: none;
    }
    .nav-link:hover {
      color: var(--primary);
      background-color: rgba(26,95,122,0.05);
    }
    .nav-cta-btn {
      background: transparent;
      border: 1px solid var(--accent);
      color: var(--accent);
      font-weight: 600;
      padding: 8px 20px;
      border-radius: var(--radius-btn);
      transition: 0.2s;
      white-space: nowrap;
    }
    .nav-cta-btn:hover {
      background: var(--accent);
      color: white;
    }
    
    /* 移动菜单 */
    .mobile-menu {
      display: none;
    }
    @media (max-width: 640px) {
      .desktop-menu {
        display: none;
      }
      .mobile-menu-btn {
        display: flex;
      }
    }
    @media (min-width: 641px) {
      .mobile-menu-btn {
        display: none;
      }
    }
    
    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.2s, transform 0.1s;
      text-decoration: none;
      box-shadow: 0 2px 4px rgba(26,95,122,0.1);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
    }
    .btn-accent {
      background: var(--accent);
      color: white;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      font-size: 1.1rem;
      transition: background 0.2s, transform 0.1s;
      text-decoration: none;
    }
    .btn-accent:hover {
      background: var(--accent-hover);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.2s;
      text-decoration: none;
    }
    .btn-outline:hover {
      background: rgba(26,95,122,0.05);
    }
    
    /* 卡片样式 */
    .card-shadow {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
      transition: transform 0.2s, box-shadow 0.25s;
    }
    .card-shadow:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: var(--primary);
    }
    
    .testimonial-card {
      background: #F1F5F9;
      border-radius: var(--radius-card);
      padding: 2rem;
      border: 1px solid #e9eef3;
    }
    
    /* 数字强调 */
    .stat-number {
      font-family: var(--font-inter);
      font-weight: 700;
      font-size: 2.8rem;
      line-height: 1.2;
      color: var(--primary);
    }
    @media (max-width: 640px) {
      .stat-number {
        font-size: 2.2rem;
      }
    }
    
    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 1.2rem 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      color: var(--text-dark);
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      color: var(--text-body);
    }
    .faq-item.open .faq-answer {
      max-height: 220px;
      padding-top: 0.8rem;
    }
    .faq-icon {
      color: var(--secondary);
      transition: transform 0.2s;
    }
    .faq-item.open .faq-icon {
      transform: rotate(180deg);
    }
    
    /* 背景辅助 */
    .bg-soft-blue {
      background: rgba(26,95,122,0.04);
    }
    
    .section-padding {
      padding: 5rem 0;
    }
    @media (max-width: 640px) {
      .section-padding {
        padding: 3.5rem 0;
      }
    }
    
    h1, h2, h3 {
      color: var(--text-dark);
      font-weight: 600;
    }
    h1 { font-size: 2.8rem; line-height: 1.2; }
    h2 { font-size: 2.2rem; }
    @media (max-width: 640px) {
      h1 { font-size: 2rem; }
      h2 { font-size: 1.7rem; }
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
      border-radius: var(--radius-card);
    }
    .hero-img-wrapper img {
      box-shadow: var(--shadow-hover);
    }
    .avatar-placeholder {
      width: 44px;
      height: 44px;
      background: #CBD5E1;
      border-radius: 50%;
      display: inline-block;
    }