Responsive design for Product Preview

I have done this in a mobile first development.

However, i have a difficuty in rectifying the following bug.

In desktop view, My product image goes below, and the text container overlaps on the image a bit. (anyways i have adjusted the width to make it look like the example).

I could not find the reason for the behaviour.

it will be great if you can clarify it.

Thank you.