/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary-dark: #1A2B3C;
      --primary-bright: #00C48C;
      --bg-light: #F8F9FB;
      --card-white: #FFFFFF;
      --text-heading: #1F2329;
      --text-body: #5F6B7A;
      --text-muted: #C9CDD4;
      --shadow-sm: 0 4px 12px rgba(26, 43, 60, 0.04);
      --shadow-md: 0 8px 24px rgba(26, 43, 60, 0.08);
      --radius-card: 16px;
      --radius-btn: 50px;
      --radius-input: 12px;
      --transition: all 0.2s 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);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    @media (min-width: 1024px) {
      .container {
        padding: 0 48px;
      }
    }

    h1, h2, h3, h4, h5, h6 {
      color: var(--text-heading);
      font-weight: 600;
    }

    a {
      color: var(--primary-bright);
      text-decoration: none;
      transition: var(--transition);
    }

    a:hover {
      text-decoration: underline;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: var(--transition);
    }

    /* 自定义组件 */
    .btn-primary {
      background-color: var(--primary-bright);
      color: white;
      border: none;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 2px 8px rgba(0, 196, 140, 0.2);
      letter-spacing: 0.5px;
    }

    .btn-primary:hover {
      background-color: #00a87a;
      box-shadow: 0 6px 16px rgba(0, 196, 140, 0.35);
      transform: translateY(-1px);
      text-decoration: none;
    }

    .btn-primary:active {
      transform: scale(0.98);
    }

    .btn-secondary {
      background-color: transparent;
      color: var(--primary-dark);
      border: 1px solid var(--primary-dark);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }

    .btn-secondary:hover {
      background-color: var(--primary-dark);
      color: white;
      box-shadow: var(--shadow-sm);
      text-decoration: none;
    }

    .card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      height: 100%;
    }

    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }

    .section-title {
      font-size: 28px;
      font-weight: 600;
      color: var(--text-heading);
      margin-bottom: 16px;
    }

    @media (min-width: 768px) {
      .section-title {
        font-size: 40px;
      }
    }

    .section-desc {
      font-size: 18px;
      color: var(--text-body);
      max-width: 700px;
      margin: 0 auto 48px;
      text-align: center;
    }

    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(255, 255, 255, 0.85);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 0 rgba(0,0,0,0.02);
      transition: background 0.3s, box-shadow 0.3s;
    }

    .navbar.scrolled {
      background: rgba(248, 249, 251, 0.95);
      box-shadow: 0 2px 12px rgba(26, 43, 60, 0.06);
    }

    .nav-link {
      color: var(--text-heading);
      font-weight: 500;
      margin: 0 12px;
      transition: color 0.2s;
      white-space: nowrap;
    }

    .nav-link:hover {
      color: var(--primary-bright);
      text-decoration: none;
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: var(--bg-light);
      padding: 24px;
      box-shadow: var(--shadow-md);
      flex-direction: column;
      gap: 20px;
      z-index: 40;
    }

    .mobile-menu.active {
      display: flex;
    }

    /* FAQ 手风琴 */
    .faq-item {
      background: var(--card-white);
      border-radius: var(--radius-card);
      padding: 20px 24px;
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
      cursor: pointer;
      transition: var(--transition);
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      color: var(--text-heading);
      font-size: 18px;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      color: var(--text-body);
      line-height: 1.6;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }

    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--primary-bright);
    }

    .faq-icon {
      font-size: 24px;
      transition: transform 0.2s;
      color: var(--text-muted);
    }

    /* 数字滚动效果简单示意 */
    .stat-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--primary-dark);
      line-height: 1.2;
    }
    @media (min-width: 768px) {
      .stat-number {
        font-size: 64px;
      }
    }

    /* 背景图区域 */
    .hero-bg {
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .hero-overlay {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(2px);
    }