body {
    background-color: slategray;
}
canvas {
    position: absolute;
    right: 0;
    left: 0;
    top: 0;
    bottom: 0;
    margin: auto;
    background-color: steelblue;
    max-height: 99%;
    max-width: 99%;
    aspect-ratio: 1;
}
#pause {
    position: absolute;
}