Flexbox align-self property not transitioning?

问题

I've tried creating a morphin "button", which slides on a further menu.
The idea was based on Codrops Morphing Buttons Concept

Now It's almost set up and there are only 2 minor things that annoy me:

• When "closing" the menu the buttons drop to the bottom immidiately although I've set the
  align-items property in the transition. Does Flexbox not support transition on said property?
• The glyphicon doesn't adjust itself with align-items and justify-center therefore I've had to get it done dirty by adjusting the top property.

I'm kinda out of ideas..

JSBin example

来源：https://stackoverflow.com/questions/33629146/flexbox-align-self-property-not-transitioning