如何移除javafx按钮下的阴影线

.button {
    -fx-focus-color: transparent; /* 移除聚焦时的阴影线 */
    -fx-faint-focus-color: transparent; /* 移除默认的微弱聚焦阴影线 */
}

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class RemoveButtonShadow extends Application {
    @Override
    public void start(Stage primaryStage) {
        Button btn = new Button("Click Me");
        
        // 加载CSS文件
        btn.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());
        
        StackPane root = new StackPane();
        root.getChildren().add(btn);
        
        Scene scene = new Scene(root, 300, 250);
        
        primaryStage.setTitle("Remove Button Shadow Example");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}