> Markdown version of [Styling a Widget](https://vaadin.com/docs/v8/framework/gwt/gwt-styling). Section index: [llms.txt](https://vaadin.com/docs/v8/framework/llms.txt)

# <a id="gwt.styling"></a>Styling a Widget

To make your widget look stylish, you need to style it. There are two basic ways to define CSS styles for a component: in the widget sources and in a theme. A default style should be defined in the widget sources, and different themes can then modify the style.

## <a id="gwt.styling.class"></a>Determining the CSS Class

The CSS class of a widget element is normally defined in the widget class and set with setStyleName(). A widget should set the styles for its sub-elements as it desires.

For example, you could style a composite widget with an overall style and with separate styles for the sub-widgets as follows:

```java
public class MyPickerWidget extends ComplexPanel {
    public static final String CLASSNAME = "mypicker";

    private final TextBox textBox = new TextBox();
    private final PushButton button = new PushButton("...");

    public MyPickerWidget() {
        setElement(Document.get().createDivElement());
        setStylePrimaryName(CLASSNAME);

        textBox.setStylePrimaryName(CLASSNAME + "-field");
        button.setStylePrimaryName(CLASSNAME + "-button");

        add(textBox, getElement());
        add(button, getElement());

        button.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent event) {
              Window.alert("Calendar picker not yet supported!");
            }
        });
    }
}
```

In addition, all Vaadin components get the v-widget class. If it extends an existing Vaadin or GWT widget, it will inherit CSS classes from that as well.

## <a id="gwt.styling.default"></a>Default Stylesheet

A client-side module, which is normally a widget set, can include stylesheets. They must be placed under the public folder under the folder of the widget set, a described in ["Specifying a Stylesheet"](https://vaadin.com/docs/v8/framework/clientside/clientside-module.md#clientside.module.stylesheet).

For example, you could style the widget described above as follows:

```
.mypicker {
	white-space: nowrap;
}

.mypicker-button {
	display: inline-block;
	border: 1px solid black;
	padding: 3px;
	width: 15px;
	text-align: center;
}
```

Notice that some size settings may require more complex handling and calculating the sizes dynamically.