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              <div class="wrapper">
  <div class="tunnel tunnel1"></div>
  <div class="tunnel tunnel2"></div>
  <div class="tunnel tunnel3"></div>

  SVG Background Images Performance tips!

  1. The FPS gets better the smaller the SVG file.
  2. Set your vector graphic's artboard/canvas to be as close to the reproduced size as possible. When in doubt as to the final size, go large. With vectors, larger canvases don't take more bytes than small ones, but they'll render nicer, especially in FireFox.
  3. To avoid sub-pixel anti-aliasing between tiled images, make sure your artboard is in whole pixels.
  4. In Illustrator, save as SVG 1.1 and "Clip to artboard!"
  In the CSS and markup!
  Originally I tried to do multiple animated backgrounds, like I've done before with PNGs: http://24ways.org/2012/flashless-animation/
  But the performance was TERRIBLE, especially in FireFox and on my iPhone 4s. Then @askoth made a demo doing the same thing by arranging the background into several div tiles and using translate to animate them upward: https://codepen.io/anon/pen/ulbHA

  What happens is that rather than calculating the background CONSTANTLY, the browser is able to "bake" a few tiles and shift them around. This gives us very nearly 60fps in Chrome and makes it look great in Firefox.
              html { height: 100%;}
body { background: #000; height: 100%;}
@keyframes fall {
  0% { 
    transform: translate(0, 0)
  100% {
    transform: translate(0, -900px)

.wrapper {
  background: #5A4F4A;
	margin: 0 auto;
  width: 530px; height: 100%;
  overflow: hidden;
  position: relative;

.tunnel {
  animation: fall 6s linear infinite;
	width: 100%; height: 900px;
		url(http://stash.rachelnabors.com/codepen/alice/bg-tunnel-border-left.svg?1) 0 0 repeat-y,
		url(http://stash.rachelnabors.com/codepen/alice/bg-tunnel-border-right.svg?1) 100% 0 repeat-y,
		url(http://stash.rachelnabors.com/codepen/alice/bg-tunnel-furniture-comp900.svg) top center repeat-y,
		20px 150px, 
		20px 150px, 
		auto 900px,
		auto auto
  position: absolute;
  left: 0; top: 0;

.tunnel2 {
  top: 900px;

.tunnel3 {
  top: 1800px;
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