Custom style for menu items

import sys

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *


class MainWindow(QMainWindow):

    def __init__(self, parent=None):
        super().__init__(parent)

        self.setWindowTitle("Custom Menu Item")

        availableGeometry = self.screen().availableGeometry()
        self.resize(640, 480)
        self.move( int((availableGeometry.width() - self.width()) / 2), int((availableGeometry.height() - self.height()) / 2))

        action1 = QAction("QAction Item 1", self)

        action2 = QAction("QAction Item 2", self)
        action2.setCheckable(True)

        action3 = QAction("QAction Item 3", self)


        checkBox = QCheckBox("QWidgetAction", self)
        checkBox.setStyleSheet("background-color: tomato;")

        widgetAction = QWidgetAction(self)
        widgetAction.setDefaultWidget(checkBox);


        menu = self.menuBar().addMenu("Menu")
        menu.addAction(action1)
        menu.addAction(action2)
        menu.addAction(widgetAction)
        menu.addAction(action3)


if __name__ == "__main__":

    app = QApplication(sys.argv)

    window = MainWindow()
    window.show()

    sys.exit(app.exec_())