Mobile and Tablet Menu background – how to change its background and text colors

I’m having an issue with the menu in this theme. The menu, in the mobile, drops down to reveal a black background. If you look closely you can see the text is there but is too dark to be visible. This has resulted in the need to create another menu next it, which is undesirable. You can see a link to the screenshot here. Anyone having this issue or know how to change? I’ve tried through the customization and searching the CSS to no avail.