ZK: CSSでグリッドヘッダの色を変更

<window title="Grid Header" border="normal">
<style> 
div.grid-head th{ 
background-color: red; 
} 
</style> 
<grid >
  <columns>
    <column width="150px" label="Author"/>
   <column width="300px" label="Title"/>
   <column width="150px" label="Manufacturer"/>
   <column width="100px" label="ProductGroup"/>
  </columns>
  <rows>
   <row>
     <label value="Sidney Sheldon"/>
     <label value="Master of the Game"/>
     <label value="Warner Books"/>
     <label value="Book"/>
   </row>
...
</rows>
</grid>
</window>