Top navbar occludes header after clicking side nav link

[freddyaboulton]

Thanks so much @freddyaboulton, super helpful!

Small note: when you click on a link in the sidebar, the top navbar overlaps the section heading so you can't read the section heading:

This is a separate, pre-existing issue that applies to all anchor links so we can tackle separately

Originally posted by @abidlabs in #12976 (review)