Created with HTML5 (BEM), CSS3 (flexbox)

It's a simple concept if you designed your site first for desktop screen sizes like 1400px then you need to scale down your design using max-width media queries and if you designed your webpage for mobile first screen sizes like 375px then you use min-width media queries to scale up your design.

Here is an MDN page for the same although this contains a lot of details and might confuse you so here is a youtube video for the same.

Nice work on this challenge! I typically recommend sticking to min-width media queries. Working mobile-first and using min-width queries has a number of positives. It can often lead to less CSS code and has the benefit of loading in fewer styles for mobile users, which can be a nice performance gain. A lot of developers often find it to be a more efficient workflow once they're used to it as well.

Keep up the great work!