Responsive product preview card component using CSS Flexbox

Hello everyone,

this is my first challenge here and also first code I'm showing someone who can understand it. I would like to hear your opinion on general structure of the code and if there are some major mistakes that you wouldn't find in real life coding.

Also for some reason when I check it on a mobile phone, it looks ok on one, but the other doesn't display it properly (both phones have same width). Any suggestions on what in the code can be causing it?

Thank you and have a nice day

Klara