Dark background and light text firefox add-ons good for night mode

If you surf the internet using Firefox web browser at night, you will find the white background and dark text too bright for the eyes. To change the background to black and light text, use the Dark Background and Light Text 0.5.5 add-on in Firefox.

Add-on is available in Firefox and it’s source code at https://github.com/m-khvoinitsky/dark-background-light-text-extension