Unofficial Dark Theme for Messenger.com
This is an unofficial extension that changes the appearance of the Messenger.com to a much darker. It's much more pleasant for the eyes at night, and even during the day.
Just click the extension icon to toggle on/off dark theme.
How to use:
Install extension, go to messenger.com and click on extension icon. That's all!
NEW: Dark Theme works on chats open in messenger application at facebook.com