When the inner container and the outer container have the same name, how is the CSS compiled? _html/css_WEB-ITnose

The question is the same as above. Although the writing is wrong, I want to know how to compile the inner and outer containers with the same name? What is written is messy. I have tried it and I want to know how it is compiled.
It is not a form of class combination. Each layer has only one class name, such as:

Reply to the discussion (solution)

It mainly depends on your style, and your closing rate is so low. No wonder no one answered

Just use height border width

Then inherit two classes
One is aa
The other is bb cc
Write common css in aa
Just write bb and cc separately
Didn’t the original poster write this before?

I know this. I am asking how the CSS is compiled under the same name, not whether the code is standardized. . .

Similar names are allowed
Isn’t it allowed to be used for multiple divs?

As for display confusion, it’s a matter of how you use it