Code is here.
I tried position: absolute and fixed but those don’t seem to work.
Do you mean you want to make it transparent instead? Then I would change background-color to transparent and the text in the “footer” to something that fits the background image (not sure white stand out enough, but difficult to say because the background image didn’t load for me). But simply put, in your footer-class this might do the trick:
background-color: transparent; color: black;
Let me know how it goes.