jQuery animate right to left not working.

jQuery animate right to left not working.

I am trying to animate an element behind a UL so that when a list element is clicked, the width of the element animates left to right to encompass the list and then readjusts to its original width.

I am able to get it working for the left to right animate, but when i try to reset the Right offset to 0, it does no longer animate[from right to left].

Can someone have a look into this. 

Here is the link to fiddle.