Using pure CSS or Flexbox as a beginner

I am creating a clone website to enhance my learning of HTML and CSS. I am still at the navbar after at least 10 hours (of pure HTML and CSS) of work and I learned a lot. When looking at Stack Overflow, a top solution suggested using Flexbox.

My question is should I dig deeper with pure CSS?
Is it fine to use Flexbox?

And will Flexbox undermine my understanding of CSS and its hacks and tricks?

Are CSS hacks necessary if there are faster and easier solutions with Flexbox?

Flexbox is pure CSS. It’s totally fine to use it.


It’s not a bad thing to know how things are done without it, but who cares? You will get it while working with legacy code and solving other problems.
So use it, man.