its obvious that the last version of FF has setting issues. Something new in the config settings is preventing css mods from taking place. I know about the toolkit css item etc.... but there is something else that is not right. Maybe you should check with Apple before you release updates. Please find out what is is..you might have to talk to Apple and try different things on a Mac ....to confirm that css works.. I am running the latest.. I think its definitely a FF thing because it worked before and other fonts controlled by Mac are not having the problems that the bookmarks toolbar is having regarding css to enlarge the microscopic font that in on a Mac toolbar. If you cant find anything then I guess its time to go to Brave.