Four card feature section - Flexbox

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

I’d love to know how to make the cards the same size across different devices, I used max-width and max-height but one of the cards has a different height.

Also, I usually design in px first and then convert the measurements to rem— is there a better practice for this?

I’d also love to know how you decide when to use Flexbox or Grid. In this case, I used Flexbox, but I could have used Grid too.

Any suggestions on how to improve my code are welcome!