body{margin:0;padding:0;font-family:Arial,sans-serif;background-color:#f5f5f5;color:#333}.app{max-width:800px;margin:0 auto;padding:20px;text-align:center}h1{color:#4caf50;font-size:36px;margin-bottom:30px;text-shadow:2px 2px 4px rgba(0,0,0,.1)}