index.css

body {
    background-color: #000;
    color: #fff;

    /* Allow mouse dragging. */
    -moz-user-select: none;
    -ms-user-select: none;
    -o-user-select: none;
    -webkit-user-select: none;
    user-select: none;

    /* disable touch panning/zooming */
    -ms-touch-action: none;
    touch-action: none;

    /* Allow canvas to hit the edges of the browser viewport. */
    margin: 0;
}

#screen canvas {
    margin: auto;

    /* Hide the gap for font descenders. */
    display: block;

    /* disable scaling interpolation */
    image-rendering: optimizeSpeed;
    image-rendering: -moz-crisp-edges;
    image-rendering: -o-crisp-edges;
    image-rendering: -webkit-optimize-contrast;
    image-rendering: optimize-contrast;
    image-rendering: pixelated;
    -ms-interpolation-mode: nearest-neighbor;
}