If all the websites you visit are stuck in dark mode, but you didn’t set it up this way in your settings, check to see if you have the extension Dark Reader installed.

If you do, please go to Extensions > Manage Extensions in the Mac menu bar, find Dark Reader on the page you get directed to, and switch the blue button off or remove the extension completely.

However, if the problem persists after doing this please submit a bug report by typing "report bug" in your Command Bar (Command-T).