Responsive e-commerce product page using SCSS/HTML/JS

Hi ! I'm glad I completed this project (even if I think I did a loooot of mistakes and useless things) but I have absolutely no idea of how to reduce a string in medium and small screens... (so I cheated a little haha).

And my slider is a little bit broken in the modal, but right now I can't think of a solution...

Any feedback is welcomed, I'm a real newbie to javascript so I would love to have some advices !