Creating a responsive live_config page

I am creating a live config page for my stream that allows for the selection of products that are in product card containers. the product cards have images and little tickboxes in the right hand corner of each card. i need to make this page responsive so that when i make the page bigger or smaller the product cards continue to look the same. for example, at the moment when i make the page smaller, the tickboxes move on top of the images. i am struggling because it is an iframe

Making something responsive is the same regardless of it being in and iFrame or not.

So you apply the same rules as you would for a regular website. Being in an iFrame doesn’t change the “how you do it”