body {
    background: #f3f0f0;
}

.container {
    padding-left: 60px;
    padding-right: 60px;
}

.center {
    text-align: center;
}

canvas {
    border: 1px solid #ccc;
    display: block;
    margin-top: 10px;
    width: 100%;
    max-width: 600px;
    height: auto;
}