mwb, things are getting too complicated here. This should really be a simple task. All the sections are the same with the exception of different widths on two. Style all the sections the same and then override the width for the two exceptions.
I forked your pen from the other thread – look at how I reduced the html and how simple it is. I didn’t even use a single class; not that that is the best approach, but just shows you don’t need so many classes and nested elements.