Rated 4 out of 5 stars

- Unfortunately version 3.0 does not provide an option to color "RSS-News & Weblogs" anymore.
Please have a look at this.

- Would also be nice if the user would be allowed to choose font sizes lower than 12

This review is for a previous version of the add-on (3.0). 

Release 3.1 fixes these problems. Both Blogs & Newsfeeds accounts and Newsgroup accounts can be colored and styled. Font sizes 10 & 11 have been added to folder/thread/message panes and compose window.