Messenger Dark Mode wót zeraye

Enable dark mode for https://www.messenger.com/. This addon don't add custom dark mode, but uses built-in theme (that can't be turned on without programming knowledge for some reason).

Facebook Messenger vs Messenger
This addon is for https://www.messenger.com/ (NOT FOR https://www.facebook.com/messages/. Facebook Messenger has dark mode that can be turned on from settings.

Source code: https://github.com/zeraye/messenger-dark-mode

If something is broken, let me know: zeraye@protonmail.com