Used pure CSS to align and center elements

What are you most proud of, and what would you do differently next time?

Nothing in particular

What challenges did you encounter, and how did you overcome them?

Vertically aligning the item to center. I set a fixed height but I'm not sure that that is optimal. Maybe switching to a full responsive design would help.

What specific areas of your project would you like help with?

How to set the right height for displaying the item at the exact center in desktop and mobile devices, since the height could be different, assuming that this is not a responsive design?