Material-UI v4 Select (override styles of the dropdown component ul & li)

materialUISelectUl.jsx

'use strict';

// https://stackoverflow.com/questions/50353676/how-to-change-the-style-of-the-dropdown-element-of-the-material-ui-select-compon

import React from "react";
import { makeStyles } from '@material-ui/core/styles';
import Select from "@material-ui/core/Select";

const useStyles = makeStyles({
    select: {
        "& ul": {
            backgroundColor: "#cccccc",
        },
        "& li": {
            fontSize: 12,
        },
    },
});

export default class MyComponent extends React.Component {

    const classes = useStyles();

    render() {
        return (
            <Select MenuProps={{ classes: { paper: classes.select } }} />
        );
    }

}