Adding scrolling to navigation drop down

Hi there, does anyone know if there’s a way to add scrolling to the drop down navigation in the Mint theme?

I have a site which has lots of pages in there and they fall off the bottom of the page of smaller screens and mobile devices…

It’s the artists drop down menu that is the issue as it has over 20 sub pages.

If you have that many pages in your navigation I would instead think of different ways to organize links for your content on page. A sidebar comes to mind but it could be anything really. Twenty links is a lot for any navigation. Only the most important pages should IMHO have a place in your top tier Navigation Bar.