Remove left padding of Alert - javafx

Question

Consider this sample program which is adding a TabPane into an Alert. As you will see, there is a white padding on the left of the TabPane that I just cannot remove.
If anyone has any idea it will be great.
Code:
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
public class AlertTest extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
Scene scene = new Scene(new HBox());
primaryStage.setScene(scene);
primaryStage.show();
Alert alert = new Alert(Alert.AlertType.NONE);
alert.setTitle("");
alert.initOwner(primaryStage);
TabPane tabPane = new TabPane(new Tab("test"));
tabPane.setPadding(Insets.EMPTY);
alert.getDialogPane().setPadding(Insets.EMPTY);
alert.getDialogPane().setContent(tabPane);
alert.show();
}
}
Visual :

Answer 1

If you add css like this:
public void start(Stage primaryStage) throws Exception {
Scene scene = new Scene(new HBox());
primaryStage.setScene(scene);
//add this 3 lines
String css = Main.class.getResource("styles.css").toExternalForm();
scene.getStylesheets().clear();
scene.getStylesheets().add(css);
...
}
and in styles.css add
.dialog-pane:no-header .graphic-container {
-fx-padding: 0; /* 10px 0px 0px 10px */
}
You can find more info about the default styles in file: fxrt.jar!/com/sun/javafx/scene/control/skin/modena/modena.css
and here is the result and full code demo: