iframe add style

Ok, so my website uses the plugin: Invite Anyone and there it uses cloudsponge.com

The plugin adds:

<iframe frameborder="0" name="easyXDM_cloudsponge_default8981_provider" id="easyXDM_cloudsponge_default8981_provider" style="position: absolute; top: -2000px;" src="https://api.cloudsponge.com/address_books/provider?xdm_e=http%3A%2F%2Flamsocialclub.com&xdm_c=default8981&xdm_p=1"></iframe>

To the bottom of everypage. However, this is causing it to have a horizontal scrollbar. If I add:

left:0px;

on the element style via Firebug, the horizontal bar issue gets resolved, but I don't know where to add that CSS property. I added it to my style.css of the theme using the id of iframe element but nothing seemed to happen.

Any thoughts what can be done? I cannot find where in the code the damn iframe gets installed.

Thanks,
Giovanni

Thanks,
Giovanni