How do I get my animation to start at the bottom of the page?

I have an edge animation that looks like it starts at the bottom of the page when I view in Edge but on my HTML there is a gap between the start of the animation and the bottom of the page. They style specifies margin of 0px but there is still a gap.

Here's the page: https://dl.dropboxusercontent.com/u/250742873/web/orangeballoon/orange balloon.html

Any help would be appreciated!