body{
font-family: Arial, sans-serif;
margin:0;
background:#f5f7fa;
text-align:center;
}

header{
background:#4a6cf7;
color:white;
padding:30px;
}

.calculator{
background:white;
padding:30px;
margin:40px auto;
width:350px;
border-radius:10px;
box-shadow:0 4px 12px rgba(0,0,0,0.1);
}

input{
width:100%;
padding:12px;
margin-top:10px;
margin-bottom:20px;
border-radius:5px;
border:1px solid #ccc;
}

button{
width:100%;
padding:12px;
background:#4a6cf7;
color:white;
border:none;
border-radius:5px;
font-size:16px;
cursor:pointer;
}

button:hover{
background:#354ed7;
}

#result{
margin-top:20px;
font-size:20px;
font-weight:bold;
}

.content{
max-width:800px;
margin:auto;
padding:20px;
text-align:left;
}

footer{
margin-top:40px;
padding:20px;
background:#eee;
}