/* roulang page: index */
:root {
      --font-stack: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }
    body {
      font-family: var(--font-stack);
      color: #0D1117;
      background-color: #F8F9FA;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .hero-bg-overlay {
      background: linear-gradient(135deg, rgba(15, 23, 42, 0.94) 0%, rgba(13, 17, 23, 0.88) 100%);
    }
    .card-hover-fx {
      transition: transform 0.2s ease-out, border-color 0.2s ease-out, box-shadow 0.2s ease-out;
    }
    .card-hover-fx:hover {
      transform: translateY(-3px);
      border-color: #00B5AD;
      box-shadow: 0 10px 25px -5px rgba(0, 181, 173, 0.1);
    }
    .faq-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
    }
    .faq-open .faq-content {
      max-height: 500px;
      transition: max-height 0.3s ease-in-out;
    }
    .faq-open .faq-icon {
      transform: rotate(180deg);
    }
    html {
      scroll-behavior: smooth;
    }