Hey Tom
It was because I couldn’t get the border stroke to go full width like the header -but thanks to you just noticed I wasn’t targeting the parent element but nav#site-navigation .inside-navigation
Then still thought not working, but your above comment made me think and noticed under layout I had the navigation width set to contained 🙁
All sorted now Tom!
Once again, thank you so much for guidance
Have a great weekend
Darron