how many features does CSS - the language - have now in comparison to JavaScript?
How many features do the various APIs altogether have.
How many features do the various object models have, CSSOM, SVG DOM, HTML DOM, Shadow DOM...
What is your knowledge of all these features in comparison to CSS features?
Jumping off of that and go look at any mature language and CS subject, there is probably too much for you "know" completely, but there is of course possibility to "know" a general argument for how to use it properly, once that is known individual things is just looking up syntax.
ok evidently someone thought that all of these things are easier to know than CSS, which is just ludicrous, and gave me a downvote to let me know their disapproval of my opinion.
I wouldn't get too hung up on downvoting online, ignoring deliberately malicious actors the range of reasons for downvoting can go from "this person posted a hate crime" to "other people already posted something close enough to this" or even "this person gave a perfectly valid answer but it does not feel like it's taking the discussion in the direction I feel it's meant to go"
I know, just every now and then it is particularly weird and I comment. Also it was real quick, like I had said something so offensive it needed to be pounced on. :)
How many features do the various APIs altogether have.
How many features do the various object models have, CSSOM, SVG DOM, HTML DOM, Shadow DOM...
What is your knowledge of all these features in comparison to CSS features?
Jumping off of that and go look at any mature language and CS subject, there is probably too much for you "know" completely, but there is of course possibility to "know" a general argument for how to use it properly, once that is known individual things is just looking up syntax.