Changing a single element of the widget style

How to chang开发者_StackOverflow社区e single element of the widget style in GWT. I would like to create new version of TextBox style, so that only the border color changed to red, for example.How to get to the style responsible for the TextBox?

I tried to create new style

.gwt-TextBox.invalid {
border-color: red;
}

but it does not work.

---

1. Make sure you add class invalid to your TextBox:

   textBox.addStyleName("invalid");
   

2. Use CssResource to associate your CSS file with GWT: http://code.google.com/webtoolkit/doc/latest/DevGuideUiCss.html#cssfiles