I would go for Bootstrap and Elm. Bootstrap gives you all the responsiveness you need to go across platform. It's basically a HTML and CSS library. Everything

I would go for Bootstrap and Elm. Bootstrap gives you all the responsiveness you need to go across platform. It's basically a HTML and CSS library. Everything you need to create UI. Then I would use the Elm programming language. Why ? Because it's a gateway to Haskell, you'll learn loads.