Rated 5 out of 5 stars

Thank you, thank you, thank you! You've saved my Thunderbird experience I was about to uninstall due the the new dark/light themes in 68 not working for me font wise.

This review is for a previous version of the add-on (12.1). 

Account Colors 13.0 has now been released.

This version is compatible with Thunderbird's Light and Dark Themes - and includes 15 new font and background coloring options to allow more precise configuration.