ASP.NET ListView - Scrollable with fixed headers using CSS

I am using an ASP.NET ListView control and, at the moment, I have a scrollable grid: (example below is simplified and contains embedded styling for sake of question) ``` <asp:ListView ID="ListView" runat="server" DataKeyNames="Id"> <LayoutTemplate> <div style="height:225px; overflow:auto;"> <table runat="server"> <tr> <th> <span>Column1</span> </th> <th> <span>Column2</span> </th> <th> <span>Column3</span> </th> </tr> <tr id="itemPlaceholder" runat="server" /> </table> </div> </LayoutTemplate> <ItemTemplate> <tr id="items" runat="server"> <td class="first"> <%#Eval("Column1")%> </td> <td> <%#Eval("Column2")%> </td> <td> <%#Eval("Column3")%> </td> </tr> </ItemTemplate> </asp:ListView> ``` I'd like to apply CSS such that my headers are fixed. What styling can I add to make it work?