it seems I use flexbox whenever I can -> improved some details

I put the illustration inside the card container. Overflow: hidden will cut the image and shadow off at the edge of the container. I put the box outside of the card container and used absolute positioning. Not the best solution to move it into place, it took a lot of trial and error.

Wrap all of your main content in a main tag and I think it will clear all of those warnings in the report.

Download AXE DevTools and you can fix accessibility warnings while you code. https://www.deque.com/axe/devtools/

Hope this helps

I would try both and see what works. I try not to use positioning at all so I am not an expert with it. Don't want to give out the wrong information.