Can you add option for changing dark and light modes by data from css: prefers-color-scheme: dark.
Thanks!

Thank you so much for making this, this is something I've wanted for ages

absolutely love it

Useful

Congratulations on a well-earned recommendation from Mozilla.

The options always reset when i restart firefox.

Simple UI, works like a charm

Working well. Wish it could change my themes every (n)hours. I have a collection of themes, you know.

Just what I wanted. Thank you!
It changes the Firefox theme when my system theme changes.
This along with Dark Reader makes life easy.

I use the "Change themes based on the system theme" and it works so perfectly. Thank you Simon!

So perfect. This is exactly what I need.

This is one of the best addons for Firefox.

Maybe a Release for Thunderbird 78?