Changing the default system font used by Iceweasel/Firefox on Debian Etch

What I mean with system font here is the font that is being used in the menu bar.. etc. That would include anything that is shown in the About window, task bar, tab bar. For this exercise we will use terminus. This may not be the best font for menus as this is a fixed width font i think. Anyway, we need to first install the font first.

~: su
#: apt-get install terminus
#: exit
~: cd ~/.mozilla/firefox

Here you need to determine what is the first part of *.defualt. Once you have the name then do change into that directory, example:

~: cd xpwzepdt.default

Now make a copy of userChrome-example.css

~: cp userChrome-example.css userChrome.css

Do edit the file, then make the following changes

# ~: nano -w userChrome.css
# this one will set the default system Iceweasel font to terminus

* {
font-family: terminus !important;
font-size: 8pt !important;
}

Enjoy! ~ts