Weird size since an update

Hello !
I use the Snaps theme since a long time, but after the last update, all the fonts of my website became shapeless, much too big. I am beginner, so i just go in the css.style and change all the fonts in 91%, waiting for a true resolution. How can i fix the problem ?
My website is https://www.hative.fr
Thank you so much, i hope you’ll understand my request in spite of my bad english.:)
Clara-Cavatina