fixed obscure shifting-content-under-firebug bug
fixed obscure shifting-content-under-firebug bug

sometimes firebug adds temporary div elements to the dom while
highlighting other elements (the padding/margin/content overlay),
which was breaking my clever body:last-child rule.

dimagi/rapidsms-contrib-apps-dev,rapidsms/rapidsms-contrib-apps-dev,rapidsms/rapidsms-contrib-apps-dev,dimagi/rapidsms-contrib-apps-dev