html, body, 
 main {
    height: 100%;
    width: 100%;
    margin: 0;
    background: #222222;
    overflow: hidden;
}

main {
    display: flex;
    align-items: center;
    justify-content: center;
}

canvas {
    height: auto;
    width: auto;
    max-width: 100%;
    max-height: 100%;
}

canvas {
    max-width: 100%;
    max-height: 100%;
    margin: auto;
    overflow: auto;
    position: fixed;
    object-fit: contain;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}