Thanks for the reply.
I do understand the issues with the volume and complexity of CSS!
Maybe a list of some of the important ones as well as any, “you really don’t want to mess with this”, items? For example, SUBTABS and PAGETABS are quite useful things to know about.
I do use Chrome as my primary browser, and am intimately familiar with Inspect. I also have a decent understanding of Bootstrap and am having good results doing most things with that. It’s been a slog, but I am making progress!