Should CSS be Constraints?

CSS is hard. The layout rules are quite complex. Most people don't know the details. Centering a <div> is famously a challenge. Remember the 2000s, when A List Apart would run all sorts of crazy ways to achieve the "Holy Grail" layout—a header, a main body and sidebar of equal heights, and a footer? Should CSS layout—given that it's such a mess—just be thrown out, to start over with a totally…