title: Slider transition doesn't work in firefox
body: <p>I created an example here: <a href="http://cssdeck.com/labs/oyjlyupw" rel="nofollow">http://cssdeck.com/labs/oyjlyupw</a></p>
  
  <p>Even though the transition is defined for firefox, it doesn't seem to animate in my Firefox 21.0 at least.
  I've tried lots of permutations and putting the transition properties on different elements, but I can't seem to solve it.</p>
  
  <p>Any help would be appreciated, thanks!</p>