Consider TableView section of the CSS guide. It has subsections called Pseudo-classes and Substructure. However, there is almost no visual aids to distinuish them from the next one which is TextArea. All the titles are h4, there are not indents.

I believe Pseudo-classes and Substructure should be visually different from TableView and TextArea titles. Also it would have been nice to use some sort of indents to group topics nicely.