Apologies for the tone in my previous comment. I guess it came off pretty harsh. Good work on creating and releasing something to the public. Upon looking again today, I like the overall approach you've taken and it seems very reasonable.
The `container-side` thing just feels very opinionated to me. I'm not sure it belongs in a framework, but that's totally your call.
As I tried, scrolling in a scroll-view (the overflow:auto section) is not smooth, <select> element is ugly, and the <pre><code> even not working (although it might be the website's problem, not the framework's, it proved that they didn't tested on mobile)
Skeleton has another major issue, it overrides the default styles of <input>s and <table>s, making it very hard to set it back. This is not friendly to third-party libraries. As far as I can see, no other frameworks did this.
I haven't had any of those problems... but if you don't like something it does just delete those lines. I'm not hard line about these things, it's just my favourite one.
I think the question is who is your target customer. If you are building a website that focus on mobile user, it's no need to design and test for desktop.
In this case Mobi.css is a choice. You can show a QRCode to guide people to mobile.
Actually Bootstrap v4 provides an opinion to use flex box instead of the traditional grid. http://v4-alpha.getbootstrap.com/getting-started/flexbox/
I would say your suggestion is good. I don't have a convincing reason that `container-side` being a part of the framework. I'll consider to remove it.
What kind of content is never visible on mobile? `Scan the QRCode to view on mobile` and `Go to top` is a kind of this content.
Why does it have to be on the side? I think it's a good design to guide people to view on mobile. Or where do you think it can be?
Thanks!