canvas {
    display: block;
    width: 100vw;
    height: 100vh;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

#err {
    display: none;
    position: fixed;
    inset: 0;
    background: #111;
    color: #f88;
    font: 16px monospace;
    padding: 40px;
    white-space: pre-wrap;
    z-index: 10;
}