I really like this and have added it to my "dive into on the weekend" bucket. The catch phrase got me: "UI composition in pure HTML"... but a bit of my optimism left when I realized that the page wouldn't scroll (there's not even a scrollbar) without JavaScript. But still, it's better than a blank page (and the header had enough info to tempt me to white list it!).

This is just a get-off-my-lawn nitpick/feature request - because I think it looks really interesting, great work!