@awesomerobot thanks for taking the time to look into this and to consider the PR.
Just one minor point of note - in those comparisons it looks like the category name max-widths weren’t increased in the 360px version.
If the category name max-widths are increased along with the menu max-width, it helps avoid the truncation of category names.
To me, the truncation of category names is a serious UX problem which unfortunately is not solved by adding only an extra 20px to the menu width