Accordion (drop-down) menu is not working/not responsive


A new to OPS and I have a couple of questions:

  1. The accordion menu seems not working on small screens (smartphone, ipad, …).
    Only three vertical lines are visible but nothing else will be displayed when clicking on them! The drop-down menu “About” and “Submission link” are consequently not seeable!
  2. How to make the Submission link as a main menu, but not a drop-down sub-menu of the About menu?

Thank you in advance