A few days ago, I was testing a dark theme related add-on, but since uninstalling it, have had this issue where my theme seems to be stuck as the Dark theme that naturally comes with Firefox. When attempting to change my theme in the customize window, mousing over the Default theme does show the proper colors for it, but selecting it still shows the Dark theme colors. I tried examining my Add-ons manager, where it shows that I am still using the Default theme, despite the colors clearly belonging to the Dark theme. I can freely change to the Light theme without issue, but for some reason, the Default one refuses to load properly. I have since tried uninstalling all my Add-ons, deleting my profiles, and uninstalling Firefox before restarting my computer, but to no avail. The Add-on I was examining initially was the Dark Night Mode add-on. Examining the page info, it does say it is not perfect, and their home page says that there are complex issues with getting it to work with Firefox, but I was unable to find more information on this offhand, nor any descriptions of scenarios like mine. I believe the initial settings for my Default theme came from some setting based off my color scheme I have set for my computer themes in general, based off my background, but I was unable to find more information on this at the time. The screenshots I am including are of my Add-on manager showing that I am using the default theme, the customize menu showing the Default theme when highlighted in the drop down menu to change it, and the result that displays when the Default theme is selected. Any ideas on why this issue is occurring, and how to fix it, would be appreciated.