@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
@-moz-document url(chrome://browser/content/browser.xul) {
tab[selected="true"] > hbox,
tab[selected="true"] > toolbarbutton {
    background-color: #f88 !important;
    font-weight:bold !important;
}
}