import mx.styles.StyleManager;
private var myDynStyle:CSSStyleDeclaration;
private function initApp():void {
myDynStyle = new CSSStyleDeclaration('myDynStyle');
myDynStyle.setStyle('color', 'blue');
myDynStyle.setStyle('fontFamily', 'georgia');
myDynStyle.setStyle('themeColor', 'green');
myDynStyle.setStyle('fontSize', 40);
StyleManager.setStyleDeclaration("Button",myDynStyle, true);
}