Fluid Menu to Overlay Content CSS3 Animations

I would like to share with you a personal experience I had while trying to build advanced visual animations with CSS keyframes. The topic we’re going to address is animating several HTML elements simultaneously and taking advantage of keyframe flexibility. To explain this subject, we will create a simple fluid menu based on four squares. Clicking on one of them will display an overlay showing related content, closing the overlay will reverse the process showing the default menu. All delays will be managed directly with CSS — no javascript timeout() here.