public class Gui extends JPanel{

    JPanel glavni = new JPanel();
    Izgled izgled = new Izgled();
    
    public Gui() {
    	izgled.setOpaque(false);
    	glavni.setOpaque(false);
    	glavni.add(izgled);
        this.add(glavni);
        
    }


private void pozadina(Graphics2D g2) {
GradientPaint pozadina = new GradientPaint(
0, this.getHeight() / 4,
new Color(176, 20, 75),
this.getWidth() - 80, 0,
new Color(24, 37, 82), true);
g2.setPaint(pozadina);
g2.fill(new Rectangle2D.Double(
0, 0, this.getWidth(), this.getHeight()));
}


@Override public void paintComponent(Graphics g) {
        super.paintComponent(g);
        
        Graphics2D g2 = (Graphics2D) g;
        pozadina(g2);
    }  
}