Adjust colors so they are the same

IPython/html/static/tree/less/tree.less

@@ -56,12 +56,12 b' ul.breadcrumb {'
 .list_container {
   margin-top: @dashboard_tb_pad;
   margin-bottom: 5*@dashboard_tb_pad;
-  border: 1px solid @border_color;
+  border: 1px solid @table-border-color;
   border-radius: @border-radius-base;
 }
 
 .list_container > div {
-  border-bottom: 1px solid @border_color;
+  border-bottom: 1px solid @table-border-color;
   &:hover .list-item{
     background-color: red;
   };