Applying css to a sharepoint gridview

Within my web-part, I want to make the header row of a gridview match the css from the sharepoint css class called ms-ContentAccent1-bgColor(I want to match the theme of the site). However, when I apply the css to the Headerstyle with the Css-Class it does not apply it. Is there any way I can apply the css while using the sharepoint gridview?

<Sharepoint:SPGridView runat="server" 
AutoGenerateColumns="False" 
ID="grid" 
EmptyDataText="There isn't any no Data"  
HeaderStyle-CssClass="ms-ContentAccent1-bgColor" 
AlternatingRowStyle-BackColor="ControlLightLight" 
>