Laura pointed out the footer floats when you have a screen long enough to show all the content at once, @jiwalker-usgs found this https://codepen.io/cbracco/pen/zekgx online and it seems to work for me.
You basically make the footer absolute, and to have it keep moving you put padding bottom on its parent element equal to the footers height or more to have space.
Since this is such a small test sample of issue it's up to you if we want it in here,
Laura pointed out the footer floats when you have a screen long enough to show all the content at once, @jiwalker-usgs found this https://codepen.io/cbracco/pen/zekgx online and it seems to work for me.
You basically make the footer absolute, and to have it keep moving you put padding bottom on its parent element equal to the footers height or more to have space.
Since this is such a small test sample of issue it's up to you if we want it in here,