CSS styles and style sheets can be set used in FXML too. We briefly looked at this in Chapter 4, FXML, while talking about SceneBuilder.
Take a look at the following FXML code and three ways to use styles directly in the FMXL:
<!-- Setting a Style Class --><Button styleClass="my-button" /><!-- Setting a style --><Button style="-fx-min-height: 50" /><!-- Setting a whole stylesheet --><GridPane stylesheets="@style.css" />