CSS for combobox

[olgabt]

Hi,

I need to put in some combo box in my ASP.NET page
<aspropDownList ID="DropDownPrefix" runat="server" TabIndex="4">
<asp:ListItem Value="0">Select One...</asp:ListItem>
<asp:ListItem>Mr.</asp:ListItem>
<asp:ListItem>Mrs.</asp:ListItem>
<asp:ListItem>Miss.</asp:ListItem>
</aspropDownList>

By feualt, it will show in blue border theme. May I know how can I use CSS to change the color theme?
Let say, change the border to #666666

Thanks in advance