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

@-moz-document url(chrome://browser/content/browser.xul) 
{
.tabs-container .tabs-closebutton {
  visibility: visible !important;
  min-height: 32px !important;
  height: 40px !important;
  margin-top: 0px !important;
  margin-bottom: 0px !important;
  margin-right: 0px !important;
  margin-left: 0px !important;
  border-top: white 2px groove !important;
  background-image: none !important;
  background-color: rgb(243, 245, 247) !important;
  padding-top: 0px !important;
  display: -moz-box !important;
  -moz-border-radius: 0px !important;
  }
}