Proposed 404 page

I've put together a fun 404 page -- maybe it is too fun, tell me what you think. The way Jekyll handles 404 pages is just straight HTML, no layouts or includes, so it's an extremely bare template with an inline `<style>` block for everything.

Desktop:

![404-desktop](https://cloud.githubusercontent.com/assets/4592/4298940/57c74c10-3e2e-11e4-83cb-1bf31fd894eb.png)

Mobile:

![404-mobile](https://cloud.githubusercontent.com/assets/4592/4298943/66a82e16-3e2e-11e4-8bdb-00480c05593b.png)

What do people think? Will this fly?