Looks great, one thing that irks me is the grid classes.
Not a huge fan of "pure-u-1-3"
Not a huge fan of "pure-u-1-3"
Compare "span4" vs "pure-u-1-3"
Sometimes I've create things like this: .pad_10_5_20_10 to avoid having to declare each one separately, but I'm sure there's a more-elegant way to do it. Of course, I can always define that padding directly in a more-generic class-name like .sidebar .... but there are cases where a pad class is more-desirable.
/spacing.css/ /* spacing helpers p,m = padding,margin a,t,r,b,l,h,v = all,top,right,bottom,left,horizontal,vertical s,m,l,n = small(5px),medium(10px),large(20px),none(0px) */
Why not use something like "2-cols/2-columns/pure-2"?
pure-row, pure-col-1-2.....
Maybe the other problem is : Units are not in multiplies of 5 and that forces you unnecessarily to think. If it would be in fixed units like bootstrap or in multiplies of 5 ( pure-u-3-25 etc.) i would be less thinking while deciding the length of some div.