/* roulang page: index */
:root {
            --primary: #1E40AF;
            --secondary: #0284C7;
            --accent: #0D9488;
            --darkslate: #0F172A;
            --surface: #F8FAFC;
        }
        html { scroll-behavior: smooth; }
        body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif; }
        .hero-pattern {
            background-color: #0B132B;
            background-image: radial-gradient(rgba(30, 64, 175, 0.25) 1px, transparent 1px), radial-gradient(rgba(2, 132, 199, 0.15) 1px, #0B132B 1px);
            background-size: 40px 40px;
            background-position: 0 0, 20px 20px;
        }
        details summary::-webkit-details-marker { display: none; }
        details[open] summary svg { transform: rotate(180deg); }