html, body {
    margin: 0px;
    padding: 0px;
    overflow: hidden;   /* avoid scrollbars */
    background-color: #1e1e1e;
    display: flex;  /* center canvas */
    justify-content: center;
    align-items: center;
}

canvas {
    display: block;
    image-rendering: pixelated;
    height: 100vh;
    object-fit: contain;    /* preserve aspect ratio */
}