This avoids the complex mutliply-nested blocks and makes the block style less reliant on a custom class. On mid-sized screens, we switch to plain horizontally-overlapping rectangles, and on small screens we stack the columns, and vertically-overlap.
Looking at ITCSS, it appears the last level should be `utilities`. Since that's a name that has no negative connotations, let's use that instead. Also add a README documenting each folder's use.
