Wikipedia has the articles, and Wikiwand makes them beautiful.
As far as I can tell, every page is ported (it may even be converted dynamically).
And yes, I mean it when I say Wikiwand makes the articles beautiful. The pages are responsive, well displayed and organised. Wikiwand also provides style personalisation, to which I am a big fan of.
A highly recommended tool! I personally only use the Google Chrome Extension.