//making a red button in javafx
Button button = new Button("My Button");
button.setStyle("-fx-background-color: #ff0000; ");
/*can address these properties: */
-fx-border-width
-fx-border-color
-fx-background-color
-fx-font-size
-fx-text-fill
/* see source for more examples
see JavaFX CSS Reference Guide for additional properties:
https://docs.oracle.com/javafx/2/api/javafx/scene/doc-files/cssref.html
*/