<?xml version="1.0" encoding="utf-8"?>
  <mx:Application 
    xmlns:mx="http://www.adobe.com/2006/mxml" 
    layout="vertical">
  
    <mx:Script>
      <![CDATA[
        import mx.controls.Alert;
  
      import mx.styles.StyleManager;
      import mx.events.StyleEvent;
  
      private var lastCSS:String;
      private function changeCSS( name:String ):void
      {
        // If you do not unload the last style
        // previous style settings will be in affect
        unloadCSS( false );
        var styleEvent:IEventDispatcher = 
          StyleManager.loadStyleDeclarations( name, true );
        lastCSS = name;
      }
      private function unloadCSS( updateFlag:Boolean ):void
      {
        if( lastCSS )
          StyleManager.unloadStyleDeclarations( lastCSS, updateFlag );
      }
      ]]>
    </mx:Script>
  
    <mx:Panel id="pnlApp" title="Sample Application"
      paddingBottom="10" paddingLeft="10" 
      paddingRight="10" paddingTop="10"
      layout="vertical" horizontalAlign="center">
      <mx:Label 
        text="Please fill out the form below and click on Login!" />       
    <mx:Form>
      <mx:FormItem label="Username:">
        <mx:TextInput id="txtUsername" />
      </mx:FormItem>
      <mx:FormItem label="Password:">
        <mx:TextInput id="txtPassword" displayAsPassword="true" />
      </mx:FormItem>    
    </mx:Form>
      <mx:Button id="btnTrace" label="Login" styleName="sLogin" />
    </mx:Panel> 
    <mx:HBox>
      <mx:Button id="btnUnload" cornerRadius="0"
        click="unloadCSS( true )" 
        label="one"
        fillColors="[#7C929D,#CCCCCC]" />
    <mx:Button id="btnBlue" cornerRadius="0" 
      click="changeCSS( 'blueCSS.swf' )" 
      label="two"
      fillColors="[#336699,#5588BB]" />
    <mx:Button id="btnRed" cornerRadius="0" 
      click="changeCSS( 'redCSS.swf' )" 
      label="three"
      fillColors="[#993333,#BB5555]" />   
    </mx:HBox>
  </mx:Application>