/* roulang page: index */
:root {
      --primary-dark: #0f172a;
      --secondary-dark: #0b0f19;
      --accent-purple: #6366f1;
      --accent-cyan: #06b6d4;
      --accent-green: #10b981;
      --accent-amber: #f59e0b;
      --surface-light: #f8fafc;
      --border-color: #e2e8f0;
      --border-dark: rgba(255, 255, 255, 0.08);
    }
    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
    }
    body {
      background-color: #ffffff;
      color: #334155;
      overflow-x: hidden;
    }
    .hero-gradient {
      background: radial-gradient(circle at top right, rgba(99, 102, 241, 0.15), transparent 45%),
                  radial-gradient(circle at bottom left, rgba(6, 182, 212, 0.12), transparent 40%),
                  #0b0f19;
    }
    .stat-glow {
      text-shadow: 0 0 20px rgba(6, 182, 212, 0.4);
    }
    .custom-scrollbar::-webkit-scrollbar {
      width: 6px;
      height: 6px;
    }
    .custom-scrollbar::-webkit-scrollbar-thumb {
      background: #cbd5e1;
      border-radius: 3px;
    }
    .hover-lift {
      transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .hover-lift:hover {
      transform: translateY(-4px);
      box-shadow: 0 16px 32px -8px rgba(15, 23, 42, 0.08);
    }
    details > summary {
      list-style: none;
    }
    details > summary::-webkit-details-marker {
      display: none;
    }
    details[open] summary .faq-icon {
      transform: rotate(180deg);
    }