gistfile1.less

body {
	background-color: #333;
	margin: 0;
	padding: 0;
	overflow: hidden;
}

canvas, img {
	image-rendering: optimizeSpeed;
	image-rendering: -moz-crisp-edges;
	image-rendering: -webkit-optimize-contrast;
	image-rendering: optimize-contrast;
	-ms-interpolation-mode: nearest-neighbor;
}

#game canvas {
	margin: 0 auto;
}

.__fullscreenCanvas() {
	background-color: #333;
	
	canvas {
		position: absolute;
		top: 0; left: 0; right: 0; bottom: 0;
		margin: auto !important;
		width: auto !important;
		height: 100% !important;
	}
}

:fullscreen {
	.__fullscreenCanvas
}

:-webkit-full-screen {
	.__fullscreenCanvas
}

:-ms-fullscreen {
	.__fullscreenCanvas
}

:-moz-full-screen {
	.__fullscreenCanvas
}

gistfile2.css

body {
  background-color: #333;
  margin: 0;
  padding: 0;
  overflow: hidden;
}

canvas,
img {
  image-rendering: optimizeSpeed;
  image-rendering: -moz-crisp-edges;
  image-rendering: -webkit-optimize-contrast;
  image-rendering: optimize-contrast;
  -ms-interpolation-mode: nearest-neighbor;
}

#game canvas {
  margin: 0 auto;
}

:fullscreen {
  background-color: #333;
}

:fullscreen canvas {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto !important;
  width: auto !important;
  height: 100% !important;
}

:-webkit-full-screen {
  background-color: #333;
}

:-webkit-full-screen canvas {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto !important;
  width: auto !important;
  height: 100% !important;
}

:-ms-fullscreen {
  background-color: #333;
}

:-ms-fullscreen canvas {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto !important;
  width: auto !important;
  height: 100% !important;
}

:-moz-full-screen {
  background-color: #333;
}

:-moz-full-screen canvas {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto !important;
  width: auto !important;
  height: 100% !important;
}