Nav Bar Mobile Underline Weight Help

Hi all. J

I’ve worked out how to add an underline to navigation links on mobile view using Foundry’s nav bar stack but can’t figure out how to make it bolder. Something like the attached image.

Any ideas are very welcome! Cheers

You’ll need to share your custom code otherwise people don’t know what you’ve done to get to where you’re at or how to advise you further.