Stats Card Component using Flexbox

This one actually took me some time to fully understand, I ran into a lot of issues with the layout as I moved up in size.

Questions:

1. What color is the image overlay? I tried to get it exactly perfect but eventually said, "good enough".

2. Is there a better way to add an overlay to an image than what I did?

3. Is my responsive styling too much? I wanted it to be completely fluid, but I feel that I went overboard on the breakponts

4. Any advice on my typography would be great!

Thank you!