You can't use Firefox extensions or code in userChrome.css that modify the appearance of the menu bar or its drop down menus.

On Mac the menu bar is maintained by the Mac OS, so you will have to look in its settings to adjust the font size.

You can try to remove the Firefox plist file (org.mozilla.firefox.plist).

• http://www.macfixit.com/article.php?story=20060606082246983 How .plist files become corrupt and troubleshooting the results

Go to "~/Library/Preferences" and remove the plist file for Firefox (org.mozilla.firefox.plist)

I'm only a little tech savvy. Before I remove the plist file, what purpose would that serve? I know where it is and how to delete it.

Also, in Apple System Preferences> Appearances> ...Text smoothing [dropdown], I am able to change the setting to 12 and that increases the Menu Bar size somewhat. Ideally it would go to 14 and 16, and possibly 18 for the visually impared.

Thank you