H1 Font suddenly enlarges in desktop window

Site URL: https://mcnaegroup.squarespace.com/config/

Website: https://mcnaegroup.squarespace.com/config/
Password: studio@mcnaegroup1

I have a H1 heading which looks great in a full window, and in mobile view...but if you make the desktop window slightly smaller the text suddenly jumps bigger.

I thought changing the tablet text size might help but i had no success. Can any one help?

//mobile text size//
@media only screen and (max-width: 767px) {	   h1 { font-size: 35px !important; line-height:115% }}
//tablet text size//
@media screen and (max-width: 960px){	   h1 { font-size: 35px !important; }}

SOLVED:

I added this to Custom CSS

h1 {font-size: clamp(4.3rem, 1vw, 35px) !important;}