Footer element with static position

HI,

I have variable height scrollable vertical arrangement followed by a fixed height horizontal arrangement. I want the fixed height horizontal arrangement to always be at the same place at the bottom of the screen, like a fixed position footer. I have this working when when the variable height scrollable vertical arrangement is larger then a available space but not when it is smaller. When smaller the bottom arrangement rises.
How to make the fixed height horizontal arrangement always be at the bottom of the page regardless of the size of the elements above it?