Background is cutting off at the end of content

I'm working on a website to showcase my photography and I'm styling it开发者_StackOverflow社区 now. Unfortunately it seems the background gradient I have made cuts off once the content finishes.

See here: http://shutterfoc.us/PoloroidGallery/nature.html

I can't seem to think of why it's doing this, although it seems it should be pretty obvious.

Any ideas?

---

Do this:

html {
    min-height:100%;
}

body {
    height:100%;
}