I’m new to Anki, so am trying to figure out how to do a couple of basic things. I have downloaded and read the Anki manual, as well as looking at some YouTube videos, but still remain a bit confused.
So, here are my questions:

How can I categorize my decks in such a way that they will independent of the ‘parent’ deck? I saw, on YouTube, that if you make a ‘subdeck’ below a main deck, using a colon, then the ‘subdeck’ will be treated as part of the main deck, which means that you would not be able to review then independently; e.g., if my parent deck is ‘Calculus’ and my ‘subdecks’ are ‘Integration’ and ‘Differentiation,’ I want to be able to look at my integration cards independently from my differentiation cards.

Using the above example, how would I make the ‘parent’ category card (Calculus). The desired resulting list of decks would look like this:
Calculus
**Integration**
**Differentiation**
 Is it possible to boldface the decks, as shown?
Any help would be much appreciated.