Documentation versions (currently viewingVaadin 8)

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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.

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:

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() {

        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.

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".

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.