body {
    font-family: Arial, sans-serif;
    background: #f5f5f5;
    padding: 20px;
}
canvas {
    border: 2px solid #444;
    background: white;
    display: block;
    margin-bottom: 15px;
}

input {
    margin: 0 5px 5px 0;
    padding: 5px;
    font-size: 14px;
    width: 50px;
}