Styling Group components

[Steve]

I have styled my column headers as in the attached image, and wish to have the Grouped by button and spacer in the column header row styled the same way, but I can't figure out what to style. 
Any help would be appreciated, thanks,
Steve

[Yoan]

Hello Steve,

 
Actually, you can check this help article where you can get familiar with the main visual element of standard GridView. The elements you want to style are - GroupPanelItem and GridViewHeaderRow's IndentPresenter.

I suggest you to check - "Styling the Group Panel" help article, for reference. 

In order to style the GridViewHeaderRow's IndentPresenter, you can check the last post of this forum thread.

Kind regards,
Yoan
the Telerik team

[Steve]

Very helpful, thank you Yoan!