Header custom font size in mobile view

[ashley-nimativ]

https://app.hubspot.com/design-manager/6516634/templates/19887599990#module=1543060694944495

This is the page I am working with. Im trying to customize the font size in the header image on mobile view to be a bit smaller, and also would like to chose what portion of the header image shows on mobile view.  

Basically if I can have the entire header/hero image area customised for mobile view only that is what I want to do! It looks fine for desktop view. I am a designer/content editor not a developer so as much help with this customization as I can get is welcome!

[AlexanderData]

You can share the page, since the link shared above does not allow us to see it, since we are not users of your hubspot.

Have you tried adding @media? This will help you create a specific style for the mobile version.

For example: 

@media only screen and (max-width: 600px) {
.nameyourclass{
font-size: 16px;
}
}

But if you share your page better, so I can give you the exact code

Regards