when you style with css-in-js (emotion, styled-component) you can perfectly and easily deal with responsive design with this css-in-js-media which is similar with include-media and support type system(ts) :)
I see what you trying to do. So I don't have to use styled-system or xstyle just to write media queries like width={[100, 300]} or w={{xs: '100px', md: '300px'}}. Very cool. I am gonna dig in the code just in a bit. How is the performance tho? Did you get a chance to look at that?
Daku (Alpha)