html, body {
    height: 100%;
    min-height: 100vh;
    padding: 0;
    margin: 0;
    background-color: black;
}

#canvas {
    width:50vw;
    position: absolute;
    top:0;
    bottom: 0;
    left: 0;
    right: 0;
    margin:auto;
}

canvas {
    display: inline;
 }