HELP: Flexbox doesn't work

HELP: Flexbox doesn't work - student project

I can't tell why my flexbox isn't working. I run the latest version of chrome. Can someone help?HELP: Flexbox doesn't work - image 1 - student projectHELP: Flexbox doesn't work - image 2 - student projectHELP: Flexbox doesn't work - image 3 - student project