Increased page content size to allow for greater seed values

### More Entropy!
The seeder does not detect mouse movement outside of the ```<body>``` contents, so if you use the site on a large resolution monitor, there's a lot of dead space on the screen not collecting entropy from mouse movement.

This commit increases the page contents size to be 100% of the window and enable mouse movements to be collected from the entire window, rather than a smaller space.