body{font-family:Arial,sans-serif;background-color:#f2f2f2;margin:0;padding:0}.calculator{background-color:#fff;border-radius:8px;box-shadow:0 0 10px rgb(0 0 0 / .2);width:300px;margin:20px auto;padding:20px}h2{text-align:center}label{display:block;margin-bottom:5px}input[type="text"]{width:100%;padding:8px;margin-bottom:10px;border:1px solid #ccc;border-radius:4px}input[type="button"]{background-color:#007BFF;color:#fff;border:none;border-radius:4px;padding:10px 20px;cursor:pointer}input[type="button"]:hover{background-color:#0056b3}#result{font-weight:700;text-align:center;margin-top:15px}