I've been enjoying Lost (https://github.com/peterramsing/lost) with PostCSS for grids recently - it has Flexbox support which works well and keeps grid class names out of my markup.
Re: this post
Grd doesn't do anything interesting at all. Everyone is blindly obsessed with flexbox. Grd doesn't even concern itself with gutters.
Here's something I cooked up in 5 minutes that does more with less code: http://codepen.io/corysimmons/pen/eZgZzz?editors=1100
I've been enjoying Lost (https://github.com/peterramsing/lost) with PostCSS for grids recently - it has Flexbox support which works well and keeps grid class names out of my markup.