Increase Mobile Font Size for h2 Font on 7.0 Mobile

Does anyone have successful CSS code for changing (increasing) the font size for all h2 (which was customized / added via CSS also) on mobile for a 7.0 site?

Right now it is auto adjusted and too small to read well - nothing I've tried has increased it.

This is the only CSS code on the site currently:

//ADDING FAUSTINE FONT//
@font-face {    
font-family: 'FAUSTINE';       
src: url('https://static1.squarespace.com/static/5eea800e6385741968b229a0/t/5eea89046135707218c2a4cb/1592428806283/Faustine.otf'), url('https://static1.squarespace.com/static/5eea800e6385741968b229a0/t/5eea9b82c4a8215ca75caca6/1592433539390/Faustine.woff');
}

//ASSIGN FAUSTINE FONT//
h2 {font-family: 'FAUSTINE';}

UPDATE:

This code works for h1 and h3 - it seems my customization of h2 font is throwing things off. Anyone have a workaround for this issue?

//MOBILE FONT SIZE//
@media screen and (max-width: 640px) {h2 {font-size: 1.5rem}}

Can you share link to a page where you use h2? We can check easier