Four Card Feature Section using CSS, HTML, and Flex

Slowly speeding up the work flow which has been really encouraging. I added flex for a few elements which definitely helped the layout. I would love your feedback. Feel free to go into my code and let me know if I am writing code harder than it needs to be!

I also noticed that overall, my work is smaller than what the solution should be. But while I am working on it through a webpage, the size is quite large. Any idea on how I can fix this to accurately display the proper size?

Thanks!