title: How override Material UI Popover CSS classes in Select component in React
body: <p>I am using <a href="https://material-ui.com/components/selects/" rel="nofollow noreferrer">Material UI Select component</a> inside my React project.</p>
  <p>I am trying to override the CSS class <code>.MuiPaper-root</code> and or <code>.MuiMenu-list</code>.</p>
  <p>My Select component:</p>
  <pre><code>&lt;Select
    value={selectValue}
    disableUnderline
    onChange={handleChange}
    css={styles.select}
  &gt;
    {cities?.map((city) =&gt; {
  
      return (
        &lt;MenuItem
          key={city.value}
          value={city.value}
          css={styles.selectItem}
        &gt;
          {city.label}
        &lt;/MenuItem&gt;
      );
    })}
  &lt;/Select&gt;
  </code></pre>
  <p>Below isn't working?</p>
  <pre><code>export default ({ theme }: StylesProps) =&gt; ({
   select: css`
     .MuiPaper-root {
        background-color: red;
      }
   `,
  });
  </code></pre>