Rated 5 out of 5 stars

This is a really nice theme, thank you. A question: is it possible to have the theme also applied to messages? (and message previews). The white (or any other colour) monochrome background kind of ruins it.

update after answer #1: Thanks. I guess a Thunderbird option to "allow themes for text-only messages" or similar might help a bit.

This review is for a previous version of the add-on (2.0.21). 

Thanks, and messages are not themed on purpose, because that is content that is send by someone else to you and sometimes styled by the sender. So a theme should not change that IMHO.