body {
    display: flex;
    flex-direction: column;
    align-items: center;
    font-family: Arial, sans-serif;
    background: lightcyan;
}
#canvas {
    border: 1px solid black;
    margin-top: 20px;
}
.controls {
    margin-top: 20px;
}
.controls button {
    margin: 5px;
}