[ned]

Flexbox is the most underrated CSS modules out there. Making flexible layouts based on the size of the viewport without it is either a major pain or flat out impossible without resorting to JS.

I don't understand why all the CSS efforts are being put into elaborate effects (transforms, blend modes, compositing, etc) when we can't yet effectively create UI layouts. Other underrated property is the non-standard "-webkit-line-clamp" (or "-o-ellipsis-lastline" for Opera), that allows you to cut off with an ellipsis a block of text after a given number of lines.

It's such a shame that the idea of constraints-based layout (the UI layout method of OSX 10.8) in CSS was never adopted: http://www.cs.washington.edu/research/constraints/web/ccss-u...