I have the exact same issue as the following users, and have yet to find a solution to the problem. "In MacOS Big Sur 11.1 on my MacBook, I have set MacOS to automatically switch between Light Mode and Dark Mode. But I notice that Firefox does not handle this well. When I have used my MacBook Dark Mode and switch back to Light Mode, Firefox still hangs in Dark Mode. The only way to solve this is to choose Light Mode in System Preferences instead of automatic." [[https://support.mozilla.org/en-US/questions/1324111]] [[https://support.mozilla.org/en-US/questions/1334201]] [[https://support.mozilla.org/en-US/questions/1264027]]