Changing the Top-level menu font colour for Mobile Device

Hi,

First of all, a big thanks for this website-saving plugin!

I want to change the font colour of the top-menu only for mobile devices. Currently, the font colour is a shade of blue for desktop and mobile. The menu looks fine for desktop but because the theme makes the background colour as dark blue for the top menu for mobile devices, the top menu becomes hard to read for smaller devices like a mobile phone.

Is there a way to change the font colour to white for the top menu for mobile devices without changing the font colour of the top menu for desktop?

Here is my website: https://www.gmfadmission.in

https://www.ads-software.com/plugins/megamenu/