Flexbox Property Suggestion

[awardx]

He there, I'm using your framework in my projects. I think it is quite simple and therefore it reflects the glimpse of brilliance.

One thing that could be a great addition to this framework (in my humble opinion though), the ability to use flexbox class in a simple (w3 framework style) way. In particular vertical direction. Something similar to Responsiveness class that works similarly but only horizontally.