I'm adjusting the menu of a free theme. This mostly does what I want it to do but I do have a problem with the responsive layout. When my desktop screen window is reduces to simulate a mobile, the menu stacks up into three lines. When this happens the title of the menus can be see through the submenu. How can the submenu be made opaque to hide the underlying text? I have tried adjusting the z-index on the menus but with no luck.
It's either something else or I'm not adjusting the z-index in the right place.
Here is the site for reference.
Hope you can help. Looking forward to a response,