Why are my Divs disappearing?

Design help General
1

https://preview.webflow.com/preview/flex-issue?utm_medium=preview_link&utm_source=designer&utm_content=flex-issue&preview=ee8da45c938d5ab2d4d648c3fb54d91b&workflow=preview

This is a very basic question, but I’ll still ask away :slight_smile:

I wanted to center the container with the 3 divs in the section, but when I apply flexbox to the section, all the 3 divs disappear. Why is this happening?