CSS footer issue

url: presslock.org

footer looks fine in chrome/safari

In firefox, .social div is pushed down and the footer doesn’t extend to bottom of page.

This is a recent problem, it looked fine a couple days ago.

I’ve changed a couple divs around, but used the same CSS, etc.

No idea why chrome+firefox are suddenly so incongruent.

I am using position:relative to position the footer divs. Could that be the issue?

thanks