/* roulang page: index */
:root {
      --brand-primary: #0284c7;
      --brand-dark: #0369a1;
      --bg-slate: #f8fafc;
      --bg-dark: #0f172a;
      --text-main: #1e293b;
      --text-muted: #64748b;
      --border-subtle: rgba(226, 232, 240, 0.85);
    }
    html {
      scroll-behavior: smooth;
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
    }
    body {
      background-color: #f8fafc;
      color: var(--text-main);
      overflow-x: hidden;
      line-height: 1.75;
    }
    .custom-shadow {
      box-shadow: 0 10px 30px -10px rgba(15, 23, 42, 0.08);
    }
    .hero-slide {
      transition: opacity 0.8s ease-in-out, transform 0.8s ease-in-out;
    }
    .tab-content {
      display: none;
    }
    .tab-content.active {
      display: grid;
    }
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s cubic-bezier(0, 1, 0, 1);
    }
    .accordion-content.open {
      max-height: 1000px;
      transition: max-height 0.5s ease-in-out;
    }