div#nav-tree ul.children_ul ul.children_ul ul.children_ul a[class^="namespace"]::before {
  content: "N ";
  /* from .icon */
  font-family: Arial, Helvetica;
  font-weight: bold;
  font-size: 12px;
  height: 14px;
  width: 16px;
  display: inline-block;
  background-color: #0081FA;
  color: white;
  text-align: center;
  border-radius: 4px;
  margin-left: 2px;
  margin-right: 6px;
}