/* roulang page: index */
:root {
      --primary: #1A3B4C;
      --accent: #F28C38;
      --bg: #F8F9FA;
      --white: #FFFFFF;
      --text: #2C3E50;
      --text-secondary: #5D6D7E;
      --text-muted: #AEB6BF;
      --border: #D5D8DC;
      --shadow-card: 0 4px 12px rgba(26, 59, 76, 0.06);
      --shadow-card-hover: 0 8px 24px rgba(26, 59, 76, 0.1);
      --shadow-nav: 0 2px 8px rgba(0,0,0,0.04);
      --success: #27AE60;
      --error: #E74C3C;
      --radius-sm: 4px;
      --radius-md: 8px;
      --radius-lg: 12px;
      --section-gap: 80px;
      --section-gap-mobile: 60px;
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      font-size: 16px; line-height: 1.7; color: var(--text); background-color: var(--bg);
      -webkit-font-smoothing: antialiased;
    }
    a { color: var(--primary); text-decoration: underline; transition: color 0.2s; }
    a:hover { color: var(--accent); }
    img { max-width: 100%; height: auto; display: block; }
    h1, h2, h3, h4 { color: var(--text); margin: 0 0 0.5rem; }
    h1 { font-weight: 700; letter-spacing: -0.5px; font-size: 2.8rem; line-height: 1.25; }
    h2 { font-weight: 600; font-size: 2rem; }
    h3 { font-weight: 600; font-size: 1.4rem; }
    .section { padding: var(--section-gap) 0; }
    .container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
    @media (max-width: 639px) {
      h1 { font-size: 28px; }
      h2 { font-size: 24px; }
      .section { padding: var(--section-gap-mobile) 0; }
    }

    /* 导航 */
    .site-header {
      background: var(--bg); position: sticky; top: 0; z-index: 40;
      box-shadow: var(--shadow-nav); transition: background 0.3s, box-shadow 0.3s;
    }
    .header-inner {
      display: flex; align-items: center; justify-content: space-between;
      padding: 16px 24px; max-width: 1200px; margin: 0 auto;
    }
    .logo {
      font-weight: 700; font-size: 1.8rem; color: var(--primary);
      text-decoration: none; letter-spacing: 0.5px;
    }
    .logo span { color: var(--accent); }
    .nav-tabs {
      display: flex; gap: 6px; align-items: center; list-style: none;
    }
    .nav-tabs li a {
      display: inline-block; padding: 8px 18px; border-radius: 20px;
      font-weight: 500; color: var(--text-secondary); text-decoration: none;
      transition: all 0.2s; background: transparent;
    }
    .nav-tabs li a:hover { background: #e9ecef; color: var(--primary); }
    .nav-tabs li a.active {
      background: var(--primary); color: white;
    }
    .header-cta {
      background: var(--accent); color: white; padding: 10px 24px;
      border-radius: 30px; font-weight: 600; text-decoration: none;
      transition: all 0.25s; white-space: nowrap;
    }
    .header-cta:hover { background: #E67E22; color: white; }
    .burger { display: none; background: none; border: none; font-size: 1.8rem; color: var(--primary); cursor: pointer; }
    @media (max-width: 1023px) {
      .nav-tabs { display: none; }
      .burger { display: block; }
      .mobile-menu {
        display: none; flex-direction: column; background: white; padding: 20px;
        box-shadow: var(--shadow-card); position: absolute; top: 70px; left: 0; right: 0;
      }
      .mobile-menu.open { display: flex; }
      .mobile-menu a {
        padding: 12px 16px; border-radius: 8px; text-decoration: none;
      }
    }
    @media (min-width: 1024px) {
      .mobile-menu { display: none !important; }
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--accent); color: white; border: none;
      padding: 14px 32px; border-radius: 30px; font-weight: 600;
      letter-spacing: 0.5px; text-decoration: none; display: inline-block;
      transition: all 0.25s; cursor: pointer;
    }
    .btn-primary:hover { background: #E67E22; box-shadow: 0 4px 10px rgba(242,140,56,0.3); color: white; }
    .btn-outline {
      background: transparent; border: 2px solid var(--primary); color: var(--primary);
      padding: 12px 30px; border-radius: 30px; font-weight: 600;
      text-decoration: none; transition: all 0.25s;
    }
    .btn-outline:hover { background: var(--primary); color: white; }
    .btn-ghost {
      border: 2px solid white; color: white; background: transparent;
      padding: 12px 30px; border-radius: 30px; font-weight: 600;
    }
    .btn-ghost:hover { background: white; color: var(--primary); }

    /* Hero */
    .hero-grid {
      display: flex; align-items: center; gap: 50px; flex-wrap: wrap;
    }
    .hero-text { flex: 1 1 400px; }
    .hero-image { flex: 1 1 400px; }
    .hero-image img { border-radius: var(--radius-lg); box-shadow: var(--shadow-card-hover); width: 100%; }
    .hero-sub { font-size: 1.15rem; color: var(--text-secondary); margin: 20px 0 28px; }

    /* 卡片 */
    .card {
      background: var(--white); border-radius: var(--radius-md);
      box-shadow: var(--shadow-card); padding: 32px 24px;
      transition: all 0.3s ease; height: 100%;
    }
    .card:hover { transform: translateY(-4px); box-shadow: var(--shadow-card-hover); }
    .card-icon { font-size: 2.5rem; color: var(--accent); margin-bottom: 16px; }
    .stat-number { font-size: 2.8rem; font-weight: 700; color: var(--accent); }

    /* 证言卡片 */
    .testimonial-card {
      background: #F4F6F7; border-radius: var(--radius-md); padding: 28px;
      display: flex; gap: 20px; align-items: flex-start;
    }
    .testimonial-avatar {
      width: 60px; height: 60px; border-radius: 50%; background: var(--border);
      flex-shrink: 0;
    }
    .testimonial-quote { font-style: italic; color: var(--text-secondary); }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border); padding: 18px 0; cursor: pointer;
    }
    .faq-question {
      display: flex; justify-content: space-between; align-items: center;
      font-weight: 600; color: var(--primary);
    }
    .faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.4s ease; color: var(--text-secondary); }
    .faq-item.open .faq-answer { max-height: 200px; padding-top: 12px; }
    .faq-toggle { font-size: 1.5rem; color: var(--primary); }

    /* 页脚 */
    .site-footer {
      background: var(--primary); color: rgba(255,255,255,0.85); padding: 60px 0 30px;
    }
    .footer-grid { display: flex; flex-wrap: wrap; gap: 40px; justify-content: space-between; }
    .footer-col h4 { color: white; margin-bottom: 16px; }
    .footer-col a { color: rgba(255,255,255,0.7); text-decoration: none; display: block; margin-bottom: 8px; }
    .footer-col a:hover { color: var(--accent); }
    .copyright { border-top: 1px solid rgba(255,255,255,0.15); margin-top: 40px; padding-top: 20px; text-align: center; font-size: 14px; }

    /* 表单 */
    input, textarea {
      border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 12px;
      width: 100%; margin-bottom: 16px; font-family: inherit;
    }
    input:focus, textarea:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(26,59,76,0.1); }

    /* 图片适配 */
    .bg-cover {
      background-size: cover; background-position: center; border-radius: var(--radius-lg);
    }