How to set different application width for web and mobile style?

[powerb]

We need to set the width for web and mobile application, how to do it ?

[rik]

It doesn’t work or I don’t know.
I create dual apps. 1x for desktop and 1x for mobile.
Read this:

Suggested settings for mobile application

I understand that SC is responsive … but mobile doesn’t seem to be easy to get to. I see that others have done it and am wondering if anyone might share tips / tricks / things you learned to get things to work well on a mobile platform.