Understanding container element settings


What am I missing here?

I have created two pages on a website where I am working with Bricks for the first time. I have set some global conditions, and have created tokens and variables.

I am working on a container. Does a variable I created only work when there is a class on the container? If I put a variable on the container, nothing is happening. If I create a class, and then add the variable, the styling is applied.

I made a short Loom:
Loom of problem

Why is this?

Thank you in advance :slight_smile: