My eyes would like to thank you for this extension - it helps a lot those who want to browse the web in a more comfortable, eye-friendly way. There must be a Thunderbird version as well - is it ever planned?

This add-on attempts and almost always achieves an incredibly difficult thing. Websites are incredibly varied in the way they implement CSS so adjusting it on the fly is a monumental task. This does so in a very intelligent way and mostly works well. There are situations where you have to tweak the settings a bit but I don't see that as a negative. The fact that there are so many ways to configure things is a huge plus. A big thanks to the developers and contributors to this project. You're doing an amazing job!