/* roulang page: index */
:root {
            --brand-primary: #FF5500;
            --brand-dark: #12161A;
            --brand-surface: #1E232A;
            --brand-track: #F4F6F9;
            --brand-green: #00C853;
            --text-main: #1F2937;
            --text-muted: #64748B;
        }
        * { box-sizing: border-box; scroll-behavior: smooth; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            color: var(--text-main);
            background-color: #FFFFFF;
        }
        .mono-num { font-family: 'DIN', 'JetBrains Mono', Consolas, monospace; }
        .hero-banner {
            background: linear-gradient(135deg, rgba(18, 22, 26, 0.94) 0%, rgba(30, 35, 42, 0.88) 100%), url('/assets/images/2b0ad788b87a3dd4.png') center/cover no-repeat;
        }
        .engine-bg {
            background: linear-gradient(180deg, #12161A 0%, #1A2027 100%);
        }
        .card-shadow {
            box-shadow: 0 4px 14px 0 rgba(18, 22, 26, 0.05);
            transition: all 0.25s ease;
        }
        .card-shadow:hover {
            transform: translateY(-4px);
            box-shadow: 0 12px 28px 0 rgba(255, 85, 0, 0.12);
        }
        details summary::-webkit-details-marker { display: none; }
        details[open] summary .arrow-icon { transform: rotate(180deg); }