Is the p tag inside h2 good or bad?

Question

css

Greetings.
1) If there is a p, div, li or any other tag in the h2 tag, is this bad for the PS? Or doesn't matter?
2) There is a code fragment:

Which looks like this:

But I would like the font size to be conditionally larger. Is it possible in CSS to set conditions for the p tag, which is located specifically in h2. If yes, how?
Thanks in advance for your reply.

Answer 1

The specification for this even has a special section Subheadings, subtitles, alternative titles and taglines https://www.w3.org/TR/html50/common-idioms.html#co...
There is one of the options:

<header>
  <h2>3D films set for popularity slide </h2>
  <p>First drop in 3D box office projected for this year</p>
</header>

Answer 2

Discover the classes
the p tag is definitely bad - it has the semantics of the li paragraph - not valid at all, it's a list element..
here's an example https://codepen.io/anon/pen/eMRzyp

Answer 3

You can write sections
And here