Como alterar a cor de fundo de um Panel ao clicar em um botão

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">

  <mx:Panel id="painel" title="Seu nome:" status="Active" 
     height="300" width="200" paddingTop="10"
     paddingLeft="10" paddingRight="10" 
     paddingBottom="10">

     <mx:Button label="Vermelho" 
        click="colorir('#FF0000');"/>
     <mx:Button label="Amarelo" 
        click="colorir('#FFFF00');"/>

  </mx:Panel>

  <mx:Script>
    <![CDATA[
      private function colorir(cor:String):void{
        painel.setStyle("backgroundColor", cor);
      }
    ]]>
  </mx:Script>

</mx:Application>