Change web part title bar color

I am creating web parts in C# code in my ASP.NET app with the WebPartManager.CreateWebPart method.  How can I set the color of the bar at the top of each web part where the Title is shown?  This bar is rendered as a <TD> tag like this:
<td id="WebPartTitle_wp921482890" style="width:100%;white-space:nowrap;">
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