body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; line-height: 1.6; color: #333; max-width: 1200px; margin: 0 auto; padding: 20px; }
        h1, h2, h3 { color: #d32f2f; margin-top: 30px; }
        h1 { font-size: 2.2em; }
        h2 { font-size: 1.8em; }
        h3 { font-size: 1.5em; }
        .logo { font-size: 2.5em; font-weight: bold; color: #ff5722; text-shadow: 2px 2px 4px rgba(0,0,0,0.2); }
        nav { background: #f5f5f5; padding: 15px; margin-bottom: 20px; display: flex; flex-wrap: wrap; justify-content: space-between; }
        nav a { margin: 5px 10px; text-decoration: none; color: #333; }
        .mobile-nav-btn { display: none; background: #ff5722; color: white; padding: 8px 15px; border: none; cursor: pointer; }
        img { max-width: 100%; height: auto; margin: 20px 0; }
        .download-btn, .login-btn { display: inline-block; padding: 12px 25px; background: #4caf50; color: white; text-decoration: none; margin: 10px 0; border-radius: 5px; }
        .login-btn { background: #2196f3; }
        footer { margin-top: 50px; padding: 20px; background: #f5f5f5; }
        @media (max-width: 768px) {
            .mobile-nav-btn { display: block; }
            nav { display: none; flex-direction: column; }
            nav.active { display: flex; }
        }