Is it possible to learn HTML CSS well through Bootstrap?

Question

css

Is it possible to understand well Html CSS itself through excellent knowledge of Bootstrap? There is such an abbreviation - "FDL" (Framework driven learning) - learning something through the Framework, for example, through the Bootstrap framework, to learn to understand Html CSS itself more deeply. There is one YouTuber who advises using this method (on the same Angular, learn it to get a deeper understanding of JS itself)

Answer 1

I do not understand the essence of such questions. You will understand well when you start reading books and documentation on your chosen field. And without "good knowledge of html css" how do you plan to "know bootstrap perfectly"?