c# - How to change GridView Header Style colour for selective columns

Question

I am fairly new to asp.net webforms and I have the following code to generate a grid with two columns, I separated the columns using colours which I am able to do using e.Row.Cells[0].BackColor = Color.FromArgb(152, 251, 152);and for the second column e.Row.Cells[1].BackColor = Color.FromArgb(60, 179, 113) at the back end

what i am trying to achieve now is to colour the part of the GridView Header that is over the FirstColumn to the same colour as the first column and the second portion of the GridView Header that is over SecondCoumn to the same colour as the second column

Below is m y code

<asp:GridView ID="GridData" CssClass="Gridview" runat="server"
                                Width="100%" AutoGenerateColumns="False" OnRowDataBound="GridData_RowDataBound" ShowFooter="True">                               
                                <Columns>
                                    
                                    <asp:TemplateField ItemStyle-Width="120px" HeaderText="ColumnFirst" >
                                        <ItemTemplate>
                                            <asp:Label ID="lblLoanGiven" runat="server"></asp:Label>
                                        </ItemTemplate>

                                        <FooterTemplate>
                                            <asp:Label ID="lblTotalLoanGiven" runat="server"></asp:Label>
                                        </FooterTemplate>
                                    </asp:TemplateField>

                                    <asp:TemplateField ItemStyle-Width="120px" HeaderText="ColumnSecond">
                                        <ItemTemplate>
                                            <asp:Label ID="lblLoanGivenBalance" runat="server"></asp:Label>
                                        </ItemTemplate>

                                        <FooterTemplate>
                                            <asp:Label ID="lblTotalLoanGivenBalance" runat="server"></asp:Label>
                                        </FooterTemplate>
                                    </asp:TemplateField>

                                    
                           <PagerStyle BackColor="#3C8DBC" ForeColor="White" />
                                <HeaderStyle BackColor="#3C8DBC" ForeColor="White" />
                                <FooterStyle BackColor="#007C98" ForeColor="White" CssClass="footer-design" />
                            </asp:GridView>

Answer 1

   GridData.HeaderRow.Cells[1].Style["background-color"] = "#3CB371"; 

Found the answer the above code colours my 2porions of the GridView headers