CSS Grid - Four card feature section

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

Semantic html markup

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

Responsive design encountered with CSS Grid.

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

Please check for

1. Right use of px, em, rem, fr and %
2. Is it usefull to use CSS Grid (two cols more in desktop version than needed and one row more in mobile version than needed) to make everything responsive and centered. Thanks a lot!