You have to create a userChrome.css file. Once it is set up, if you exit FF and relaunch it, the settings will be transferred to the file that renders when you enter about:config in the location bar. The easy way to do all this is to add the chromEdit extension. It generates the needed file, complete with some sample entries that you can uncomment to use. At the bottom of that file, there is a link to http://www.mozilla.org/unix/customizing.html, which gives more information and includes more hacks, several addressing type size issues, that you can copy and paste to your own userChrome.cssfile. You don't need to know CDD to do these things, so long as you are comfortable with basics like commenting and uncommenting code. Hint: some of their sample code at the web site gives type sizes in millimeters ("mm"). You can safely switch those to point sizes ("pt"). However, there is no example given for increasing the type size of text in the title bar. But changing type sizes under KDE > Control Center > Appearance > Fonts > General worked for me, although it changes things elsewhere too. That was acceptable to me because I had system-wide type size issues because of the screen resolution I have to run to allow web sites to render properly. There is a CSS hack at the Mozilla customizing site for switching screen resolution on a per-site basis, and I have playing with it on my Todo list. But I stress that your situation may be different. I was having type size issues with many apps and more size issues than just app title bars. E.g., in Firefox, virtually everywhere text and icons appear in the controls was tiny, including toolbars. I am still looking for a system-wide fix. In the interim, installing the SphereGnome Jumbo FF theme has done wonders, although I still have tiny icons in my Google toolbar (but not type size, go figure). I still have type size issues in several non-KDE apps. BTW, running SuSE 9.3 Pro on KDE. Hope this helps. Marbux