Round Corners in java fx pane

Question

I'm trying to get round bottom corners in my application, but the result is this:

This is the CSS file:

.mainFxmlClass {
  #pane{
    -fx-background-size: 1200 900;
    -fx-background-radius: 0 0 18 18;
    -fx-border-radius: 0 0 18 18;
    -fx-background-color: #FC3D44;
  }
}

And my main class:

@Override
public void start(Stage stage) throws Exception {
    Parent root = FXMLLoader.load(getClass().getResource("Preview.fxml"));
    Scene scene = new Scene(root);
    stage.setScene(scene);
    stage.show();
}
public static void main(String[] args) {
    launch(args);
}

How can I remove these white corners?

Answer 1

Finally after so much research and some help from the spanish version of Stack O. the most easy way to remove the white corners is this:

In the main class you must add:

scene.setFill(Color.TRANSPARENT);

and:

stage.initStyle(StageStyle.TRANSPARENT);

The only problem is that StageStyle.TRANSPARENT will leave you without the close button so you must make it by yourself. The final result is this: