/* roulang page: index */
:root {
            --brand-primary: #1E3A8A;
            --brand-primary-hover: #172554;
            --brand-blue: #0284C7;
            --brand-green: #059669;
            --brand-amber: #D97706;
            --bg-base: #FFFFFF;
            --bg-surface: #F8FAFC;
            --text-main: #0F172A;
            --text-muted: #475569;
            --border-color: #E2E8F0;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: var(--font-sans, system-ui, -apple-system, sans-serif);
            color: var(--text-main);
            background-color: var(--bg-base);
            line-height: 1.75;
            overflow-x: hidden;
        }
        .tab-btn.active {
            color: #1E3A8A;
            border-color: #1E3A8A;
            background-color: #EFF6FF;
        }
        .hero-pattern {
            background-image: linear-gradient(to right, rgba(30, 58, 138, 0.94), rgba(15, 23, 42, 0.95)), url('/assets/images/a84fcb6bb1dd16e1.webp');
            background-size: cover;
            background-position: center;
        }
        .footer-pattern {
            background-image: linear-gradient(to bottom, #0F172A, #090D16);
        }