Add to cart button positioning for phone

Hey guys,

These guys https://www.dpfurnituredesigns.com/ are using woocommerce. I’d like to change the add to cart button so it appears below the images when visiting the site from a phone device so the visitor can see the whole image.

Which part of the css should I look for and do you have any easy css hack I can use for simple and quick results?

Best,

Tasos