custom css for product item block

Hello! 

Ok.. this one is a lil tricky (well, probably not for you pros!) 

I'm trying to figure out how to change the font for product blocks that are listed in the "Additional Info" within a product page

Page:  https://www.diveguideschannelislands.com/store/p/weekend-dive-trip-with-guide

Password: goldfish

It's defaulting to the sites overall h1, h2, etc but I want to actually make it look like the attached 

Any help appreciated! 

Thank you! 

yesss, that helped! thank you! 

is there a way to set the add to cart button to be a black block with white text (instead of the outline pill) 

and also make the quantity border smaller also?

Updated the code to include the button style change and the quantity input to be smaller by adjusting the padding.  Feel free to mark as a solution if everything works correctly for you!

thank you!!