Barely responsive Base Apparel page

Alright then, I struggled quite a lot and it looks decent at 375px and desktop but in between it's a mess.

Could anyone point me in the right direction?

• I used grid and the minmax function. Could that be the problem? (because I certainly don't get the hang of it yet)
• Also the background image for desktop doesn't look quite right.
• Finally, first challenge using js. It works but is it right?

I thank you all in advance!