I have the Substance template. The hornav menu does not show the drop down menu items. Reading several forum entries, I understand that the hornav menu relies on a hover state to trigger the display of sub items, and may not display on some mobile devices. Because of this, I read that you recommend to use the mobile menu across all mobile device screen sizes. How do I do this? I don't see this option to enable a mobile menu. Is there a better alternative? Thank you!