How to put space between footer and last post on home page and category pages ?

I have been trying to add a margin-top: 10px; to have space between the footer and the last post on my home page and category pages. I added this in the style footer option but that doesn't make the change even though I am seeing it in the code. I am using atahualpa 3.5.3 with latest wordpress version.I have made this possible on single post pages by adding bottom margin to the next/previous box in the bootom but cannot figure out how to add margin to the footer box. My site is at http://learnsignlanguageonline.org/