This addon fits your needs https://addons.mozilla.org/en-us/firefox/addon/black-background-white-text/

As I mentioned in my post I had already added a plug in that helps make pages Black and White, and a Theme to make double sure I could do this. It is on my Mobile Device Galaxy S5 - Here are screenshots from it: As you see the same exact Plugin was used, and a theme to insure it works However, this is the result, and an annoying one as well. No in using the browser in the dark if this is the result...

i think these pages the HOME PAGES are somehow protected from the user changing. Not sure why they would be this way, but they need to be able to be changed as well. Also NOT all of the text using the plugin translates to black and white, some of it is black on block and no that is not due to the theme being used also, it was that way before the theme was even thought of to be used... No Night mode to make all pages black BG and WHT text... No plugin I can locate so far works.