/* roulang page: index */
:root {
            --bg-base: #FFFFFF;
            --bg-alt: #F4F6F8;
            --color-dark: #0B253A;
            --color-night: #06131E;
            --color-amber: #E67E22;
            --color-emerald: #059669;
            --text-main: #1E293B;
            --text-muted: #64748B;
        }
        html { scroll-behavior: smooth; }
        body { color: var(--text-main); font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif; }
        .hero-bg {
            background-image: linear-gradient(rgba(6, 19, 30, 0.82), rgba(11, 37, 58, 0.88)), url('/assets/images/edcebf0dfbd95457.webp');
            background-size: cover;
            background-position: center;
        }
        .concept-bg {
            background-image: radial-gradient(circle at 50% 50%, rgba(15, 50, 76, 0.5) 0%, rgba(6, 19, 30, 1) 100%), url('/assets/images/2f4762bf9dfb085e.webp');
            background-size: cover;
            background-position: center;
        }
        .grid-pattern {
            background-size: 32px 32px;
            background-image: linear-gradient(to right, rgba(255, 255, 255, 0.05) 1px, transparent 1px),
                              linear-gradient(to bottom, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
        }