Reduce Margin between Tabs and Title Bar in Firefox Australis

[Update] For convenience the script has been added to

Australis has been incorporated to release channel since Firefox 29, replacing title bar with tabs bar. One thing to be picky about is that there is a margin above tabs and it wastes vertical space.

Solution 1

In Stylish add-on (, create a new user script with the following content:

:root[sizemode="normal"] #titlebar {
  margin-bottom: -60px !important;

and the gap will be removed.

Solution 2

With some further search I found this post: where "Gingerbread Man" posted another solution that is shorter but produces the same outcome:

#TabsToolbar { margin-top: 0px !important; }

I prefer this solution.



Firefox 29 Australis has a margin above tabs.


The margin is removed.