/* roulang page: index */
:root {
      --primary-color: #1e3a8a;
      --primary-dark: #0f172a;
      --accent-green: #059669;
      --accent-teal: #0d9488;
      --bg-light: #f8fafc;
      --border-subtle: rgba(226, 232, 240, 0.85);
      --font-mono: ui-monospace, SFMono-Regular, Menlo, monospace;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      color: #334155;
      background-color: #ffffff;
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }
    .num-data {
      font-family: var(--font-mono);
      font-feature-settings: "tnum";
    }
    .glass-nav {
      background: rgba(255, 255, 255, 0.94);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
    }
    .glass-card {
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(8px);
    }
    .hero-mask {
      background: linear-gradient(135deg, rgba(15, 23, 42, 0.94) 0%, rgba(30, 58, 138, 0.88) 100%);
    }
    .tech-grid-bg {
      background-image: radial-gradient(rgba(255, 255, 255, 0.08) 1px, transparent 1px);
      background-size: 24px 24px;
    }
    details > summary::-webkit-details-marker {
      display: none;
    }
    details summary {
      list-style: none;
    }
    details[open] summary svg {
      transform: rotate(180deg);
    }
    .tab-btn.active {
      background-color: #1e3a8a;
      color: #ffffff;
      border-color: #1e3a8a;
    }