body { font-family: 'Arial', sans-serif; line-height: 1.6; color: #333; max-width: 1200px; margin: 0 auto; padding: 20px; }
        h1 { color: #e74c3c; text-align: center; }
        h2 { color: #2980b9; border-bottom: 2px solid #3498db; padding-bottom: 5px; }
        h3 { color: #27ae60; }
        .nav { background: #333; padding: 10px; position: sticky; top: 0; z-index: 100; }
        .nav a { color: white; text-decoration: none; margin: 0 15px; }
        .mobile-toggle { display: none; }
        .btn { background: #e74c3c; color: white; padding: 10px 20px; border: none; cursor: pointer; }
        img { max-width: 100%; height: auto; margin: 20px 0; }
        .footer { background: #333; color: white; text-align: center; padding: 20px; margin-top: 30px; }
        @media (max-width: 768px) {
            .nav a:not(.mobile-toggle) { display: none; }
            .mobile-toggle { display: block; }
            .nav.active a { display: block; }
        }