I was thinking more of the "alpha" and "omega" mixins which made no immediate sense to me. I'm guess its part of your "golden ratio" code, but it still doesnt seem truly "semantic"

And I really dont see how Semantic.gs isn't responsive? Set its grid representation to percentages, write a few media queries, and its as responsive as any other grid system out there. The inherent behavior of the CSS box model + Percentage based semantic.gs + media queries is as responsive as I think you can get.... its all I've ever needed to do ANY responsive design I can imagine. I've never felt limited by Semantic.gs in terms of responsive design.

I really dont see how you could make that any easier? Are your mixins generating media queries? Is it really that hard to calculate a golden ratio and use it with Semantic.gs?

Edit: http://semantic.gs/examples/responsive/responsive.html they even have a Responsive example on the front page of their website, so I really dont understand why you think Semantic.gs isnt responsive?

> i.e. it doesn't come with a straightforward way to change the grid for specific breakpoints.

isn't that what media queries are for?