/* roulang page: index */
:root {
            --primary: #0F2C59;
            --accent-cyan: #00B4D8;
            --accent-green: #10B981;
            --bg-light: #F8FAFC;
            --text-main: #1E293B;
            --text-muted: #64748B;
        }
        html {
            scroll-behavior: smooth;
            font-family: system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
        }
        body {
            color: var(--text-main);
            background-color: #FFFFFF;
            overflow-x: hidden;
        }
        .hero-overlay {
            background: linear-gradient(135deg, rgba(7, 21, 43, 0.94) 0%, rgba(15, 44, 89, 0.88) 60%, rgba(0, 180, 216, 0.45) 100%);
        }
        .card-hover {
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }
        .card-hover:hover {
            transform: translateY(-4px);
            box-shadow: 0 16px 32px -8px rgba(15, 44, 89, 0.12);
        }
        .accordion-content {
            transition: max-height 0.3s ease-out, opacity 0.3s ease-out;
            max-height: 0;
            overflow: hidden;
            opacity: 0;
        }
        .accordion-content.open {
            max-height: 280px;
            opacity: 1;
        }