Sencha touch -文字颜色不同的面板

Ext.application({
    name:'myApp',
    launch:function(){
      var panel=new Ext.Panel({
                    id:'mypanel',
                    html:'一个简单的事例面板'
        });
         var subpanel=new Ext.Panel({
                  id:'subpanel',
                  html:'这事一个子面板'
         });
     //   Ext.get('mypanel').addCls('colorRed');
        Ext.Viewport.add(panel);
        Ext.ComponentManager.get('mypanel').add(subpanel);
        var newpanel= Ext.fly('mypanel');
        newpanel.addCls('colorBlue');
        var sub=Ext.fly('subpanel');
        sub.addCls('colorRed');
    }
});