/* roulang page: index */
:root {
            --primary: #0F52BA;
            --accent: #00A86B;
            --highlight: #FF5722;
            --bg-light: #F8FAFC;
            --text-dark: #0F172A;
            --text-muted: #64748B;
        }
        body {
            font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Heiti SC", sans-serif;
            background-color: var(--bg-light);
            color: var(--text-dark);
            scroll-behavior: smooth;
        }
        .hero-bg {
            background-image: linear-gradient(to right, rgba(15, 23, 42, 0.92), rgba(15, 82, 186, 0.85)), url('/assets/images/aa5967c9ab2e9cf1.png');
            background-size: cover;
            background-position: center;
        }
        .engine-bg {
            background-image: linear-gradient(to bottom, rgba(11, 19, 43, 0.95), rgba(28, 37, 65, 0.98)), url('/assets/images/90da35f903cdd137.jpg');
            background-size: cover;
            background-position: center;
        }
        .cta-banner-bg {
            background-image: linear-gradient(135deg, rgba(15, 82, 186, 0.95), rgba(0, 168, 107, 0.9)), url('/assets/images/4201ad9d8af502fb.png');
            background-size: cover;
            background-position: center;
        }
        .card-hover {
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }
        .card-hover:hover {
            transform: translateY(-5px);
            box-shadow: 0 20px 25px -5px rgba(15, 82, 186, 0.12), 0 8px 10px -6px rgba(15, 82, 186, 0.08);
        }
        details summary::-webkit-details-marker {
            display: none;
        }
        details[open] summary .faq-icon {
            transform: rotate(180deg);
        }