change CheckBoxList appearance

Hi

I used CheckBoxList in mypage

<asp:CheckBoxList ID="ChkGroups" runat="server" RepeatDirection="Horizontal" TextAlign="Left" Width="300px">

 <asp:ListItem Text="Special"  Value="Special"></asp:ListItem>
 <asp:ListItem Text="free"  Value="free"></asp:ListItem>
<asp:ListItem Text="State"  Value="State"></asp:ListItem>
   <asp:ListItem Text="Other"  Value="Other"></asp:ListItem>
    </asp:CheckBoxList>

Here I want change ListItem of Checkbox Appearance I mean I want define variable  space between ListItem when I set width for Checkboxlist it change space between ListItem equally but I want change space variable...

How I can do it?

Best Regards

Neda