Except I'm doing this mobile-first so IE9 would really need to get the desktop styles and none of the mobile. IE8 and lower get a separate stylesheet (which I've barely worked on). I could perhaps do another stylesheet for IE9 only that just locks it in desktop mode...

And yeah, resize is hefty. I just copied this from something I built a long time ago but matchMedia+polyfill really is the better way. I'm putting it on the todo list.