if you comment out this line:
/* url-prefix("file:///"), */

be aware that your local html file won't be rendered as they should be


EDIT: nov 2008, I actually don't use it anymore, I found a way better way to achieve this, without this downside mentionned above:)
see the about:config tips on this page: http://freestyler.ws/style/7229/a-basic-darktheme-for-many-sites