Add a little bit of padding to the content area when the viewport is < 768px in width.

This is related to [issue 79](https://github.com/jquery/plugins.jquery.com/issues/79) on the plugins.jquery.com repo.

Note: I haven't been able to get the environment set up locally yet. I did test this on the live site via the Chrome Inspector and it works fine.

I'm not going to be able to try to get this all set up properly until tonight so if you prefer me to test locally first, I can let you know then. Otherwise it's a tiny change so if you're ok with it, it should be ready to merge in.