Get element next to kendo widget in CSS

Question

Can I get the element next to a kendo widget? With normal inputs it works very well but the kendo widget got an parent element before the input Element so it dosen't work.

Example in kendo Dojo: https://dojo.telerik.com/apiVejuY/7

I think the problem is my css Selector:

.k-textbox.k-valid + label{
  color:green;
}

1. Works fine

.k-header .k-input.k-valid + label{
  color:green;
}

2. Don't work at all. The idea behind this one was to get the complete widget, then look if the input in this widget is valid by kendo. If it is change the label next to the widget.

The question is how do I have to change my second css selector so it works as expected?