Use Charcoal to experience Messenger (messenger.com) in dark mode. Toggling dark mode with any theme is easy: click on the Messenger icon on the top left of the web page, and set your preference. Features: Messenger icon toggle on the top left of the web page to access preferences. Choose between 3 themes: Charcoal, Midnight, and Deep Blue. Change dark or light appearance whenever you want, or set dark mode based on your device's setting.