I need a run down of the rules

HTML-CSS
1

in the threads

I.d’s start with a (#)
classes start with a (.) . . .

what are the rest of the possibilities and the rules around them? can you direct me to a reference text that breaks down the details. I like the practice but id learn faster able to reference a text.

3

Yes I considered that as well. I wasnt sure just how many existed. good to know the ones i have seen and will see will be the greater majority.

5

Two your two basic ones I would add one basic one - if there is nothing, it refers to an element, like div or h1