Set a grey ruler line ABOVE my product name and UNDER my main menu links (Supply theme)

[Mark67]

Hi!

I would like to set a grey ruler as shown in the picture. I also want it to be in a position that is equal to the distance of the header and the top of the words.  I read several topics here, but they are too old and I cannot implement them. 

Thanks in advance!

[Ted]

Hi, Mark!

Ted here from Shopify, thanks for reaching out to us!

As you are using our Supply theme, our Theme Support may be able to make these changes for you. For them to take a look, could you email support@shopify.com from the email address you use to sign into Shopify? When you do, you should receive an automated email back with a ticket number assigned. If you let me know what that ticket number is, I'll raise it further for you.

Feel free to reach out to our Support team any time as well. We're here 24/7 via Facebook, Twitter, chats, emails and phone. Just click 'talk to support’ for some more info!

Thanks a mill! 
Ted