Floating Social z-index problem

On this page (and the rest of the site too):

http://dreamweavers-quilts.com/2013/07/beginnings/

I'd like the Floating Social box to display behind the content box. I've tried to apply this CSS to the .box class:

.box {
  z-index: 7;
  position: relative;
}

and then set the z-index for Floating Social to "1" but that's not working. I'm probably not attacking the right CSS selectors or something, so if some awesome CSS guru could help me out, I'd appreciate it!