[flexcoders] CSS for spark dataGrid?

[markflex2007]

Hi,

 I use CSS for spark dataGrid, that is like

   <fx:Style>

        @namespace s "library://ns.adobe.com/flex/spark";

        s|DataGrid {

            alternatingRowColors: #FF0000, #0000FF;

        }

    </fx:Style>
    
 but I get the message:  "CSS type selectors are not supported in components: 
'spark.components.DataGrid'".

why css can not work with spark.components.DataGrid?

I use FB4.6 for mobile app now

Thanks

Mark