[Libgdx] Using progress bar as health bar

Newbie & Debugging Questions
#1

Hello, i got a problem. How can i fill in the progress bar with color? Since i would like to use it as a health bar. Also be possible to change color at any time.

public class playerHud implements Disposable {
    private Stage stage;
    private Viewport viewport;

    private Label name;

    private ProgressBar.ProgressBarStyle healthBarStyle;
    private ProgressBar healthBar;

    public playerHud(Main game, Player player) {
        viewport = new ExtendViewport(Main.V_SCREEN_WIDTH, Main.V_SCREEN_HEIGHT, new OrthographicCamera());
        stage = new Stage(viewport, game.batch);
        name = new Label(player.getName(), game.asset.getSkin());
        name.setPosition((Main.V_SCREEN_WIDTH / 2) + player.getName().length() + 15, (Main.V_SCREEN_HEIGHT / 2) + player.getHeight() + 20);

        healthBarStyle = new ProgressBar.ProgressBarStyle();
        healthBarStyle.background = game.asset.getSkin().getDrawable("default-slider");

        healthBar = new ProgressBar(0, 100, 1f, false, healthBarStyle);
        healthBar.setSize(50, 50);
        healthBar.setValue(50);

        stage.addActor(name);
        stage.addActor(healthBar);
    }

    public Stage getStage() {
        return stage;
    }

    @Override
    public void dispose() {
        stage.dispose();
    }
}