body{font-family:Arial,sans-serif;background-color:#f4f4f4;margin:0;padding:0}.calculator{background-color:#fff;max-width:400px;margin:20px auto;padding:20px;border-radius:5px;box-shadow:0 0 10px rgb(0 0 0 / .1)}h1{text-align:center;color:#06c}label,input{display:block;margin-bottom:10px}input{width:100%;padding:5px;border:1px solid #c8c8c8}button{background-color:#090;color:#fff;border:none;padding:10px 20px;border-radius:5px;cursor:pointer}button:hover{background-color:#060}#result{margin-top:10px;text-align:center;font-weight:700;color:#ff4500}