DRY Switching with CSS Variables: The Difference of One Declaration
Ana Tudor is an epic amazing designer and developer, and her ability to stretch CSS for some visual sugar is unsurpassed.

What if I told you a single CSS declaration makes the difference in the following image between the wide screen case (left) and the second one (right)? And what if I told you a single CSS declaration makes the difference between the odd and even items in the wide screen case?
An excerpt from DRY Switching with CSS Variables: The Difference of One Declaration