Mobile First Four Card Feature Section Using HTML and CSS(Flexbox)

This challenge was very useful for me in terms of building my confidence when laying out elements. Please I would like to know if I picked the best approach to aligning the cards and make them re-align down to mobile screen size. Your feedback is very important for my growth. That being said, if you could take a minute to review my work, I would really appreciate it. Thanks so much for your time.