Using JavaFX view and view controller with factory method.

FxmlView.java

import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;

public class FXMLControllerFactory {
  private FXMLControllerFactory() {}

  public static <T> T newController(Class<T> controllerType, Stage stage) {
    var filename = "/%s.fxml".formatted(controllerType.getSimpleName());
    try {
      var url = controllerType.getResource(filename);
      var loader = new FXMLLoader(url);
      loader.setRoot(stage);
      loader.load();
      return loader.getController();
    } catch (Exception e) {
      throw new IllegalStateException("Could not load view from file: %s".formatted(filename), e);
    }
  }
}

style.css

/* Inspired by UWP Type Ramp
 *
 * | Title     | Weight           | Size | Line Height | Ratio |
 * |-----------|------------------|------|-------------|-------|
 * | Header    | light (300)      | 46px | 56px        | 3.286 |
 * | Subheader | light (300)      | 34px | 40px        | 2.429 |
 * | Title     | semi-light (350) | 24px | 28px        | 1.714 |
 * | Subtitle  | regular (400)    | 20px | 24px        | 1.429 |
 * | Base      | semi-bold (600)  | 14px | 20px        | 1.000 |
 * | Body      | regular (400)    | 14px | 20px        | 1.000 |
 * | Caption   | regular (400)    | 12px | 14px        | 0.857 |
 */

.root {
  -fx-font-family: "Verdana";
}

.header {
  -fx-font-size: 3.0em;
  -fx-font-weight: normal;
}

.subheader {
  -fx-font-size: 2.25em;
  -fx-font-weight: normal;
}

.title {
  -fx-font-size: 1.5em;
  -fx-font-weight: normal;
}

.subtitle {
  -fx-font-size: 1.25em;
  -fx-font-weight: normal;
}

.body {
  -fx-font-size: 1.0em;
  -fx-font-weight: normal;
}

.base {
  -fx-font-size: 1.0em;
  -fx-font-weight: bold;
}

.caption {
  -fx-font-size: 0.875em;
  -fx-font-weight: normal;
}