addStyleName not work?

Hi all,

I just start to use vaadin and have a problem using addStyleName. Here is the details:

// code

this.priceListName = new TextField();
this.priceListName.setStyleName(“mystyle”);

//css file

.v-textfield-mystyle {
border: thin dashed;
background: white;
}

But seems addStyleName does not work at all. Does anyone know how to solve this problem?

Thanks a lot