The mixin takes arguments of start-width, start-fontsize, end-width, end-fontsize, and increment-width. It then creates media queries between those start and end points, one new query at each increment.
The HTML font-size now is
This is a first pass to just get the idea down, I'll be iterating on this idea for a bit. If you have comments, I'd love to hear from you. ( @jeffschram )
Below is the styles, I want to see how many queries this generates, maybe it's too much code?