3-column-card-component with flex

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

1. I'd like to go for a mobile-first approach when I make a similar layout again.
2. I'd like to include more IDs for the markup and specific CSS.

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

Centering the flex parent (main tag) vertically. I just added vertical padding, which isn't the best solution.

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

I require help with the following:

1. Centering the flex parent (main tag) vertically to the body. The man tag had a fixed height, and I added vertical padding to make it look better. Any tips on this will be appreciated.
2. Writing more concise CSS and feedback on the naming convention.