<window title="Application Window" border="normal" width="100%"
	height="100%" apply="com.tugrulaslan.controller.IndexController">
	<style>
	<!-- Listbox Header -->
	.z-listheader-content{
	color: green !important;
	}
	
	<!-- Listbox Cell -->
	.z-listcell-content{
	color: red !important;
	}
	
	<!-- Groupbox Header -->
	.z-caption-content{
	color: blue !important;
	}
	
	<!-- Label -->
	.z-label{
	color: yellow !important;
	}
	
	</style>
</window>

Result