Is it possible to apply a style to a DropDownList?

In order that all my controls have a consistent look and feel I have
been using classes in a style sheet. Try as hard as I might I cannot
get a border color change applied by the style. The relevant section of
the stylesheet is below:

.DataEntryDropdown
{
   color:Black;
   height:auto;
   font-family:Verdana;
   font-size:small;
   font-style:normal ;
   border-color: #B5C7DE  ;
   border-style: solid ;
   border-width:thin ;
}

Am I trying to achieve the impossible?

As I can't get this to work with a stylesheet does anyone know if it'll
work with a skin?