/* roulang page: index */
:root {
            --primary: #0056b3;
            --secondary: #00d4ff;
            --bg-light: #f9fbff;
            --text-dark: #1a1a1a;
            --text-gray: #666;
            --white: #ffffff;
            --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
            --radius: 8px;
        }

        * { box-sizing: border-box; margin: 0; padding: 0; }
        body { font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif; line-height: 1.8; color: var(--text-dark); background-color: var(--bg-light); }
        .container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
        
        /* Header */
        header { background: var(--white); padding: 20px 0; border-bottom: 1px solid #eee; position: sticky; top: 0; z-index: 1000; }
        nav { display: flex; justify-content: space-between; align-items: center; }
        .logo { font-size: 24px; font-weight: bold; color: var(--primary); text-decoration: none; }
        .nav-links a { margin-left: 30px; text-decoration: none; color: var(--text-dark); font-weight: 500; transition: 0.3s; }
        .nav-links a:hover { color: var(--primary); }

        /* Hero */
        .hero { padding: 80px 0; text-align: center; background: linear-gradient(135deg, #f0f7ff 0%, #ffffff 100%); }
        .hero h1 { font-size: 48px; margin-bottom: 20px; color: var(--primary); }
        .hero p { font-size: 20px; color: var(--text-gray); max-width: 800px; margin: 0 auto 30px; }
        .btn { display: inline-block; padding: 15px 40px; background: var(--primary); color: var(--white); border-radius: 50px; text-decoration: none; font-weight: bold; transition: 0.3s; }
        .btn:hover { background: #004494; transform: translateY(-2px); }

        /* Sections */
        section { padding: 80px 0; }
        .section-title { text-align: center; font-size: 32px; margin-bottom: 50px; }
        .grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
        .card { background: var(--white); padding: 30px; border-radius: var(--radius); box-shadow: var(--shadow); transition: 0.3s; }
        .card:hover { transform: translateY(-5px); }
        .card h3 { margin-bottom: 15px; }

        /* Footer */
        footer { background: #1a1a1a; color: #ccc; padding: 40px 0; text-align: center; }
        footer a { color: var(--white); text-decoration: none; margin: 0 10px; }

        /* Utilities */
        .bg-white { background: var(--white); }
        .text-center { text-align: center; }
        @media (max-width: 768px) {
            .grid-3 { grid-template-columns: 1fr; }
            .hero h1 { font-size: 32px; }
        }