Responsive (Really) Social Proof Section Flexbox

Hello everyone! It's me again, with another challenge and questions. I'd like to ask, how do you keep your content responsive for mobile devices? I've tried a few steps, and it's probably because, in desktop sizes, I've given some width and height to the elements, but still is there any shorthand for like limiting the screen size to the contents size or something like that, if you know what I mean :D I've seen something like that. Still, I forgot it now and it's a bit messy around to look for the right content online. I'm having some difficulties from time to time. If there's someone who would like to explain it to me, I'd be very glad to hear him/her. Thanks in advance, have a nice one, everyone!