/* roulang page: index */
:root {
      --primary: #0F52BA;
      --primary-dark: #0A3B85;
      --accent: #00A86B;
      --bg-surface: #F4F7FB;
      --text-main: #1A202C;
      --text-sub: #4A5568;
      --border-color: #E2E8F0;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      color: var(--text-main);
      background-color: var(--bg-surface);
      font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      line-height: 1.68;
    }
    .hover-lift {
      transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    }
    .hover-lift:hover {
      transform: translateY(-4px);
    }
    .accordion-content {
      transition: max-height 0.35s ease-out, opacity 0.3s ease-out;
      max-height: 0;
      opacity: 0;
      overflow: hidden;
    }
    .accordion-item.active .accordion-content {
      max-height: 220px;
      opacity: 1;
    }
    .accordion-item.active .accordion-icon {
      transform: rotate(180deg);
    }
    /* Mobile nav drawer */
    #mobileDrawer {
      transition: transform 0.3s ease-in-out, opacity 0.3s ease-in-out;
    }