Product Card Project - Solution

I lost my sanity with this project.

Questions.

1. Why is the div "product-info" not the same size as the "image-container" div? how can i assure that the elements inside a flexbox are always the same size?

2.In order to fit text into a container, whats better to define more space for the text, padding or margin? I had a hard time aligning the text inside the info div.

3. Is it correct to create the desing for the mobile first and then create a whole media query for the desktop design, or there are easier approaches to this?