body {
    font-family: Arial, Helvetica, sans-serif;
    background-color: white;
    margin: auto;
    width: 600px;
    border: 3px solid blue;
}
h1 {
	color: blue;
	margin-top: 0;
}
main {
    padding: 1em 2em;
}
div {
	margin-bottom: 0.5em;
}
label {
	float: left;
    width: 16em;
    text-align: right;
}
input {
    margin-left: 1em;
}
#calculate {
	margin-bottom: 1em;
}