Border not showing in front end

Hi
I've added a bottom border to a heading element.
It's showing in the backend but not in the front end. Any ideas why?
This is the page:
https://sheabutterxo.com/sheabutter-xo-shop/
Each title should have a bottom border.

This is a screenshot of the backend: https://www.dropbox.com/s/gwgphi9p4zmtid8/border-heading.jpg?dl=0

Thanks!
DAn