@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

:not(menulist) > menupopup > menuitem,
menupopup > menu,
popup > menuitem,
popup > menu {
  padding-left: 0 !important;
  padding-right: 0 !important;
}

menupopup .menu-text,
popup .menu-text {
  margin-left: 20px !important;
}
menupopup .menu-iconic-text,
popup .menu-iconic-text {
  margin-left: 0 !important;
}

menupopup .menu-iconic-left,
popup .menu-iconic-left {
  width: 20px !important;
  margin-left: 0 !important;
  margin-right: 0 !important;
}