/* roulang page: index */
:root {
            --primary: #0891b2;
            --primary-dark: #0e7490;
            --accent: #f97316;
            --surface-bg: #f8fafc;
            --text-main: #0f172a;
            --text-muted: #334155;
            --border-color: #e2e8f0;
        }
        * { box-sizing: border-box; }
        body { font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif; color: var(--text-main); background-color: var(--surface-bg); }
        .hero-bg {
            background-image: linear-gradient(rgba(15, 23, 42, 0.88), rgba(15, 23, 42, 0.92)), url('/assets/images/f02a7131f2fa9503.webp');
            background-size: cover;
            background-position: center;
        }
        .stats-bg {
            background-image: linear-gradient(rgba(14, 116, 144, 0.94), rgba(15, 23, 42, 0.95)), url('/assets/images/bc5c01e9bd9c8ce9.jpg');
            background-size: cover;
            background-position: center;
        }
        .cta-bg {
            background-image: linear-gradient(rgba(8, 145, 178, 0.94), rgba(14, 116, 144, 0.96)), url('/assets/images/39bbaea747e79a24.jpg');
            background-size: cover;
            background-position: center;
        }
        details > summary { list-style: none; }
        details > summary::-webkit-details-marker { display: none; }
        details[open] summary svg { transform: rotate(180deg); }
        .smooth-scroll { scroll-behavior: smooth; }