body { font-family: 'Arial', sans-serif; line-height: 1.6; color: #333; max-width: 1200px; margin: 0 auto; padding: 20px; }
        .mobile-nav { display: none; }
        @media (max-width: 768px) {
            .desktop-nav { display: none; }
            .mobile-nav { display: block; }
            .toggle-btn { background: #ff9900; color: white; border: none; padding: 10px; cursor: pointer; }
        }
        h1 { color: #e67e22; border-bottom: 3px solid #e67e22; }
        h2 { color: #2980b9; }
        h3 { color: #27ae60; }
        .download-btn, .login-btn { background: #2ecc71; color: white; padding: 12px 25px; margin: 15px 0; text-decoration: none; display: inline-block; border-radius: 5px; }
        .login-btn { background: #3498db; }
        img { max-width: 100%; height: auto; margin: 20px 0; }