0 => Force a Dark background
   1 => Force a Light background
   2 => Follow the System theme (default in Firefox 94)
   3 => Follow the Browser toolbar theme (default in Firefox 95+) 

'''SOLVED BY jscher2000 ON THIS POST - https://support.mozilla.org/en-US/questions/1363924''' --------------------------------------------------------------------------------------------------------------- B) Built-in pages, and websites that have light/dark responsive themes Starting in Firefox 95, Firefox would inform pages that you preferred a light/dark theme based on your Firefox toolbar theme instead of your system theme. There is a way to decouple your page (content) theme preference from your toolbar theme. At this point, it's only available through the back door... (1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk. More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future. (2) In the search box in the page, type or paste layout.css.prefers-color-scheme.content-override and pause while the list is filtered (3) Double-click the preference to display an editing field, and change the value to whatever you prefer from the list below, then press Enter or click the blue check mark button to save the change. 0 => Force a Dark background 1 => Force a Light background 2 => Follow the System theme (default in Firefox 94) 3 => Follow the Browser toolbar theme (default in Firefox 95+) The about:config page should immediately reflect your saved change.