Boxes are messed up in Firefox[SOLVED]

Hi,

I’m trying to figure out what’s causing the weird behaviour in Firefox. Here is the link to my page
here

The page is shown perfectly in Chrome, but Mozilla doesn’t show it properly. What’s interesting is that if you resize the browser’s window, or click on “inspect element - basically anything that changes the size of your current window”, the app works perfectly again. How can I fix this issue?

This is what it looks like (Chrome on the left, Firefox on the right).

Edit: I’ve solved the issue by changing flex-flow: column wrap; to flex-flow: column;