body {
    font-family: Arial, Helvetica, sans-serif;
    background-color: white;
    margin: 1em auto;
    width: 640px;
    padding: 1em;
    border: 1px solid black;
    border-radius: 1em;
}
canvas {
    margin-bottom: .5em;
}
label {
    float: left;
    width: 6em;
}
input {
    margin-left: 1em;
    margin-bottom: 1em
}