Thanks. I just saw that this was opened so I figured I'd take a look. Nice job doing the components so far, I think it's a great effort. My only concern is that I'm not really a fan of the planned transition approach. Having both the old styles *and* gaia-header within the same stylesheet seems very clunky to me. I think bringing back the style_unstable/ folder and only having a very clean stylesheet folder there which we migrate apps to would be better. (We could then flip it and all apps to use just styled/.)

It also seems like this doesn't buy us a whole lot without the :content selector, and that we will have to backtrack once we have it. Do we have a bug filed for the :content selector?