Sorry for the delay. Sometimes topics are missed around here.
So, your content has nothing to do with your slider being pushed outside. That happens because your slider (or whatever that is) is not responsive while the rest of the content is. Mobile resolutions are plenty so I can’t give you one specifically.
I suggest you have a look at our documentation page and our demo site. You’ll see that Sydney allows easier ways to build the type of layout you’re trying to have on your website while also keeping it responsive. If you’re not looking for a responsive design that I’m afraid you’ll have to look for a very old theme.