Hi,

Have a look at this article from tenforums - Tabs below address bar

The necessary code needs to change as FF evolves. The article above refers to Windows 10 - FF-65-64bit and should work with Mac. I cannot say that the code will work with FF-77.

See the solution in this thread for updated userChrome.css code to move the Tab bar to the bottom position.

• /questions/1280813 73.0.1 tabs are both behind and covering navigation toolbar

See also:

• https://www.userchrome.org/what-is-userchrome-css.html
• https://www.userchrome.org/how-create-userchrome-css.html

In Firefox 69 and later you need to set this pref to true on the about:config page to enable userChrome.css and userContent.css in the chrome folder.

• toolkit.legacyUserProfileCustomizations.stylesheets = true

See:

• https://www.userchrome.org/firefox-changes-userchrome-css.html