div.tree-child {
  background: url(https://imgsvr.edgereg.net/ERImg/04/33/63/tree.png) no-repeat 11px center; 
}
div.tree-child-last {
  background: url(https://imgsvr.edgereg.net/ERImg/04/33/63/tree-bottom.png) no-repeat 11px center; 
}
[dir="rtl"] div.tree-child,
[dir="rtl"] div.tree-child-last {
  background-position: -65px center;
}
div.tree-child-horizontal {
  background: url(https://imgsvr.edgereg.net/ERImg/04/33/63/tree.png) no-repeat -11px center;
}