Add a specific font to the menu only

Hello. I want to use this google webfont: https://www.google.com/webfonts/specimen/Cuprum

only on my menu. Here is my code for the secondary menu: https://pastebin.com/R5PB3L4p

I know I use a commercial theme but I hope that someone might help me anyways.

Im currently using the cuprum font in all the body but I want to change that and keep it in the menu only.
If anyone could help me it would be very much appreciated.

Thank you!