Variations buttons don't change color when customer clicks so they think check out is not working

[neesie55]

If you go to girls dresses and click on the red and white dress, you will see you can choose 2 variations...size and fabric.  When you click any of the buttons, nothing happens visually, so my customers think that checkout is not working.  What do I need to do to fix this?  All I want is for the button to change color or give some indication that it has been clicked.  

NOTE:  The "click" DOES follow through to the cart, so the correct info is there, the customer just not know it and leaves.

Including a link so you can see for yourself:  Link