Rated 5 out of 5 stars

Love the add on, Can you make a light theme? Would be great.

This review is for a previous version of the add-on (0.8.4). 

I made a light theme. It can follow system theme, or you can select the theme. The new version is still under review, but it should update automatically when Thunderbird approves it. Change the theme under View - Themes.