body {
    margin: 0;
    text-align: center;
    background: #000;
  }
  canvas, body {
    touch-action: none;
    -webkit-user-select: none;
    user-select: none;
    -webkit-touch-callout: none;
  }
  canvas {
    image-rendering: pixelated;   /* canvas has no CSS size, so a hi-DPR screen upscales the bitmap - keep that upscale hard-edged, not the browser's default blur */
  }

svg.filters{position:absolute;width:0;height:0}