/* roulang page: index */
:root {
            --primary: #1E40AF;
            --secondary: #3B82F6;
            --bg-light: #FFFFFF;
            --bg-alt: #F8FAFC;
            --bg-dark: #0F172A;
            --text-main: #1E293B;
            --text-sub: #475569;
            --border-color: #E2E8F0;
            --radius: 12px;
        }
        body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; color: var(--text-main); background-color: var(--bg-light); line-height: 1.6; }
        .container { max-width: 1280px; margin: 0 auto; padding: 0 1.5rem; }
        .section-padding { padding: 5rem 0; }
        .btn-primary { background-color: var(--primary); color: white; padding: 0.75rem 1.5rem; border-radius: var(--radius); transition: all 0.3s; }
        .btn-primary:hover { background-color: #1E3A8A; box-shadow: 0 10px 15px -3px rgba(30, 64, 175, 0.3); }
        .card { background: white; border: 1px solid var(--border-color); border-radius: 16px; padding: 2rem; transition: all 0.3s; }
        .card:hover { transform: translateY(-5px); box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1); }
        .header-nav { position: sticky; top: 0; z-index: 50; background: rgba(255,255,255,0.95); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border-color); }
        .hero-gradient { background: linear-gradient(135deg, #1E40AF 0%, #3B82F6 100%); }