html,
body {
    margin: 0;
    padding: 0;
    background: #222;
}

main {
    text-align: center;
    width: 100%;
}

canvas {
    display: block;
}


main {
    align-items: center;
    display: flex;
    height: 100vh;
    /* Fallback for browsers that do not support Custom Properties */
    justify-content: center;
}

main canvas {
    height: auto !important;
    width: auto !important;
    max-width: 100%;
    max-height: 100%;
    display: inline-block;
    /* Instead of display: block; */
    margin: 0 auto;
    vertical-align: middle;
    touch-action: none;
}