Responsive Goodness

I started implementing a responsive layout for the Rails guides. I haven't tested it in browsers yet beyond Webkit, but I wanted to get feedback before putting more than a few hours into it. You can check out my changes at:

https://github.com/joefiorini/docrails/compare/responsive

Feel free to pull my fork and try it out on an iPhone. I'm planning on adding:

1) expand/collapse for the chapters within a guide 2) in between state for tablet devices

Is this something that we want to continue on?