title: backside-visibility not working in IE10 - works fine in webkit
body: <p>I'm building a simple pure-css 'card flip' animation, it <em>has</em> to work in IE10, but sadly what I've written doesn't.</p>
  <p><a href="http://jsfiddle.net/felixthehat/7FeEz/1/" rel="noreferrer">jsFiddle demo here</a> or <a href="https://www.dropbox.com/s/kbp8rh0sbh49ixe/backside%20vis%20test%20case.zip" rel="noreferrer">sample html zip here</a></p>
  <p>I can see that backside-visibility works in IE10 from <a href="http://ie.microsoft.com/testdrive/Graphics/hands-on-css3/hands-on_3d-transforms.htm" rel="noreferrer">their demo here</a> so maybe I've just overlooked something stupid, maybe a fresh pair of eyes might help!</p>
  <p>Thanks in advance!</p>