Hi @opti8,
I hope you are well today and thank you for your question.
To achieve this you have to develop custom CSS code as developed for Sparkling theme in the following topics.
https://colorlibsupport.com/t/menu-4/
https://colorlibsupport.com/t/how-to-adjust-menu-and-font-for-mobile/
Best Regards,
Movin