Use tag, set the styles using CSS syntax
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Style> .myStyle { paddingTop: 12; paddingBottom: 12; } </mx:Style> <mx:VBox id="myVBox1" borderStyle="solid"> <mx:Button label="Submit" /> </mx:VBox> <mx:VBox id="myVBox2" styleName="myStyle" borderStyle="solid"> <mx:Button label="Submit" /> </mx:VBox> </mx:Application>