Responsive CSS help needed.

http://visionlabart.com/
The screen goes to 768 and below, the 3 clickable images with hover animation are not visually appealing / centered. I have tried to make them display differently by wrapping in a div and centering, centering each, and so many other things including left:50% for the div wrap etc.

Any help on this would be greatly appreciated.

Or if you know how to set edits for specific screen sizes that would also be very helpful.