#ce-undo-close-toolbar-button {
  list-style-image: url("chrome://cmimprove-os/skin/undo-close-tb.png");
}
#ce-undo-close-toolbar-button[disabled="true"] {
  list-style-image: url("chrome://cmimprove-os/skin/undo-close-tb-disabled.png");
}
.animation-content {
  position:fixed;
  top: 0px;
  left: 0px;
  width: 0px;
  height: 0px;
  opacity: 0;
}
