, a border is added to the menubar container when focus is within the menubar.</li>
      <li>To support operating system high contrast settings, focus is highlighted by adding and removing a border around the menu item with focus.</li>
      <li>The down arrow and checked icons are made compatible with operating system high contrast settings and hidden from screen readers by using the CSS <code>content</code> property to render images.</li>
      <li>
        Like desktop menubars, submenus open on mouse h