Rated 5 out of 5 stars

This is exactly what I needed! Now the mail does not burn my eyes in the evenings! Great, thank you!

In order for the message viewing area to also become dark, go to the preferences - display - formatting - colors - select the background color is black, the text color you want and set "override the colors cpecified by the content…" in "always".

This review is for a previous version of the add-on (12.0.2).