Help with POPUP on Login

Hi, i recently changed my joomla template.
My background keep a dark color, so i changed also my font color in "white" and modified all website to be most pretty with new template.
Problem is the Jfbconnect POPUP. Because the BACKGROUND is White by default... so now users can't see message anymore.
WHERE i can operate basically to change popup background???
I've seen it's not connected to "System Template" because System message show correctly.. so i don't know..
somebody can help me?