If you have an account you don't need an extension, you can choose the theme you prefer in the prefs: https://en.wikipedia.org/wiki/Special:Preferences#mw-prefs

If you have an account you don't need an extension, you can choose the theme you prefer in the prefs: https://en.wikipedia.org/wiki/Special:Preferences#mw-prefsection-rendering https://en.wikipedia.org/wiki/Special:Preferences#mw-prefsec...