[VelvetElvis]

For the last year or so, I've been running all books through the Edit Book function, ensuring all found issues are resolved. With recent updates to the Edit Book function, I get a lot of these warnings:

"Outlines should only be modified using: focus"

My CSS skills are basic at best. Is it safe to delete tags such as "outline: 0"?
Doing so resolves the warnings, but I don't want to cause other issues. Googling the subject hasn't helped me.