Treetable hierarchical gray scaling

Hi,

I want to give my treetable a hierarchical gray scale.
On the very top of my treetable, the row background should be gray dark.
The deeper the hierarchical layer is, the lighter the gray should go.

Any idea how to solve it?
Got a treetable hierarchy like this:
1
1.0
1.0.0
1.0.1
1.1
2
2.0
2.0.0
2.0.0.0
2.0.0.1

Hello,

You can set item $css property depending on its $level in hierarchy.

Please, check the following snippet: http://webix.com/snippet/f2a59b95