Menu in mobile devices does not show submenus

Hello,
When I view my site on mobile devices or small screens, the menu does not show sub-menus. 
 
Also, the X that closes the menu appears on the first menu item. How do I move it to the left?
My site:
www.hayatt.net

Thanks. 

Hello,

Please edit file /media/templates/site/museum/css/custom.css and around line 471 change this:
to this:

Regards,
Milos

Thank you so much.

Thanks. That removed the X to the right place. 
But still, the menu does not show the submenu items. Only the main ones. 

Hello,

On my computer, it works properly. When I click the third menu item, the submenu shows normally.

Regards,
Milos
 

I've tried it on my phone, and it does work.
Only on my computer, it does not show the submenus, not sure why.
Thanks.