/* roulang page: index */
:root {
      --primary: #E43D30;
      --primary-dark: #C53030;
      --dark: #1A1A2E;
      --accent: #FFB800;
      --bg: #F5F5F7;
      --text: #333333;
      --text-light: #666666;
      --border: #E5E5E5;
      --card-bg: #FFFFFF;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --radius-sm: 8px;
      --radius-md: 12px;
      --transition: 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      margin: 0;
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Inter', system-ui, -apple-system, sans-serif;
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }
    /* 导航 */
    .nav-blur {
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      background-color: rgba(255,255,255,0.85);
      border-bottom: 1px solid var(--border);
    }
    .nav-link {
      position: relative;
      font-weight: 500;
      color: var(--text);
      padding: 8px 0;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--primary);
      transition: width 0.25s ease;
    }
    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }
    .nav-link.active {
      color: var(--primary);
    }
    /* 按钮 */
    .btn-primary {
      background-color: var(--primary);
      color: white;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      display: inline-block;
      transition: background-color 0.25s, transform 0.2s;
      border: none;
      cursor: pointer;
      text-align: center;
      box-shadow: 0 2px 6px rgba(228,61,48,0.2);
    }
    .btn-primary:hover {
      background-color: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 6px 14px rgba(228,61,48,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 30px;
      border-radius: var(--radius-sm);
      display: inline-block;
      transition: all 0.25s;
    }
    .btn-outline:hover {
      background-color: rgba(228,61,48,0.08);
      transform: translateY(-2px);
    }
    /* 卡片 */
    .card-hover {
      transition: transform var(--transition), box-shadow var(--transition);
      background: var(--card-bg);
      border: 1px solid transparent;
    }
    .card-hover:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
      border-color: var(--primary);
    }
    .pain-card {
      background: var(--card-bg);
      border-left: 4px solid var(--primary);
      padding: 24px;
      border-radius: var(--radius-sm);
      box-shadow: var(--shadow-sm);
    }
    .testimonial-card {
      background: #f9f9fb;
      border-radius: var(--radius-md);
      padding: 28px;
      position: relative;
    }
    .testimonial-card::before {
      content: "“";
      font-size: 48px;
      color: var(--primary);
      opacity: 0.3;
      position: absolute;
      top: 10px;
      left: 18px;
      line-height: 1;
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      cursor: pointer;
      padding: 20px 0;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 1.1rem;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      color: #555;
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .faq-icon {
      transition: transform 0.3s;
      font-size: 1.2rem;
      color: var(--primary);
    }
    /* 数据数字 */
    .stat-number {
      font-weight: 800;
      color: var(--primary);
      line-height: 1.2;
    }
    footer {
      background-color: var(--dark);
      color: #ccc;
    }
    footer a:hover {
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--dark);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 32px;
        z-index: 100;
      }
      .nav-menu.open {
        display: flex;
      }
      .nav-menu a {
        color: white;
        font-size: 1.25rem;
      }
      .hamburger {
        display: block;
      }
    }