.app{width:320px;padding:10px;margin:0 auto;background-color:#f2f2f2}h2{text-align:center}form{background-color:#fff;padding:20px;border-radius:5px;box-shadow:0 2px 5px rgba(0,0,0,.1);max-width:300px;margin:0 auto}label{display:block;margin-top:10px}input[type=text]{padding:8px 2px;margin:5px 0;width:100%;border-radius:3px;border:1px solid #ccc}button[type=submit]{background-color:#4caf50;color:#fff;border:none;padding:10px 20px;margin-top:10px;cursor:pointer;border-radius:3px;display:block;margin:10px auto}button[type=submit]:hover{background-color:#45a049}#result{margin-top:20px;text-align:center;font-size:18px;color:#333}