body,
html {
    margin: 0;
    padding: 0;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    background: #000;
    color: #fff;
    font: 21px monospace;
}

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