/* roulang page: index */
:root {
      --brand-dark: #0F172A;
      --brand-charcoal: #090D16;
      --brand-teal: #0D9488;
      --brand-sky: #0284C7;
      --bg-gray: #F8FAFC;
      --border-color: #E2E8F0;
    }
    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }
    body {
      background-color: var(--bg-gray);
      color: #334155;
      overflow-x: hidden;
      margin: 0;
      padding: 0;
    }
    .custom-container {
      max-width: 1240px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.25rem;
      padding-right: 1.25rem;
    }
    .section-spacing {
      padding-top: 5rem;
      padding-bottom: 5rem;
    }
    .tech-border {
      border: 1px solid var(--border-color);
    }
    .card-transition {
      transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.25s cubic-bezier(0.16, 1, 0.3, 1);
    }
    .card-transition:hover {
      transform: translateY(-4px);
      box-shadow: 0 12px 24px -10px rgba(15, 23, 42, 0.08);
    }
    .faq-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out;
    }
    .faq-item.active .faq-content {
      max-height: 240px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }