body { font-family: Arial, sans-serif; line-height: 1.6; color: #333; margin: 0; padding: 0; }
        header { background-color: #0066cc; color: white; padding: 1rem; text-align: center; }
        nav { display: flex; justify-content: space-around; }
        nav a { color: white; text-decoration: none; font-weight: bold; }
        .mobile-nav-toggle { display: none; }
        main { padding: 1rem; }
        h1 { color: #0066cc; margin-top: 0; }
        h2 { color: #3399ff; border-bottom: 2px solid #0066cc; padding-bottom: 0.5rem; }
        h3 { color: #66ccff; }
        img { max-width: 100%; height: auto; margin: 1rem 0; }
        footer { background-color: #333; color: white; text-align: center; padding: 1rem; }
        .btn { display: inline-block; padding: 0.5rem 1rem; background-color: #0066cc; color: white; text-decoration: none; margin: 0.5rem 0; }
        @media (max-width: 768px) {
            nav { flex-direction: column; display: none; }
            .mobile-nav-toggle { display: block; background-color: #0066cc; color: white; border: none; padding: 0.5rem; }
            .nav-visible { display: flex; }
        }