如何将所有JButtons的默认鼠标按下背景颜色覆盖为其当前背景颜色的较深阴影？

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class ShadowButton extends JButton {
    private static final Color SHADOW_COLOR = new Color(0, 0, 0, 50); // 阴影颜色，可根据需求调整透明度

    public ShadowButton(String text) {
        super(text);
        setOpaque(false); // 设置按钮透明
        setContentAreaFilled(false); // 设置按钮内容区域透明
        setBorderPainted(false); // 取消按钮边框
        setForeground(Color.WHITE); // 设置按钮前景色
        setFocusPainted(false); // 取消按钮焦点样式

        addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                repaint(); // 鼠标按下时触发重绘
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                repaint(); // 鼠标释放时触发重绘
            }
        });
    }

    @Override
    protected void paintComponent(Graphics g) {
        Graphics2D g2d = (Graphics2D) g.create();

        if (getModel().isPressed()) {
            // 绘制当前背景颜色的较深阴影
            g2d.setColor(getBackground().darker());
            g2d.fillRect(0, 0, getWidth(), getHeight());
        } else {
            // 绘制按钮默认状态
            g2d.setColor(getBackground());
            g2d.fillRect(0, 0, getWidth(), getHeight());
        }

        g2d.dispose();
    }
}

import javax.swing.*;
import java.awt.*;

public class MyFrame extends JFrame {
    public MyFrame() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Shadow Button Demo");
        setSize(400, 300);
        setLocationRelativeTo(null);

        // 创建一个面板
        JPanel panel = new JPanel();
        panel.setBackground(Color.WHITE);

        // 创建ShadowButton并添加到面板中
        ShadowButton button1 = new ShadowButton("Button 1");
        ShadowButton button2 = new ShadowButton("Button 2");
        ShadowButton button3 = new ShadowButton("Button 3");
        panel.add(button1);
        panel.add(button2);
        panel.add(button3);

        // 将面板添加到窗口中
        add(panel);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            MyFrame frame = new MyFrame();
            frame.setVisible(true);
        });
    }
}