Blog preview card, using flexbox (responsive)

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

I am proud of figuring out how to calculate responsive width, but I feel like the code could be cleaner.

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

I got stuck with margins, because it didn't look quite right. Also, it was difficult to make the card responsive, as it didn't want to shrink.

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

I don't really know how to make the layout even more responsive. Under a certain width (<250px device width) the header and text start to break down in unexpected ways.