Hello, I have a situation like this:

#+BEGIN_SRC org-mode

* A
  blahbla

** B
   blahblah

*** Brief digression on B
      blahblah
      $$ some math $$

   Here I want to continue with B
   blahblha

#+END_SRC

So, that when exporting (to html or pdf/tex) the digression would appear
more indented, ore maybe even boxed. And below it the Subheading would
continue as normal.
I guess this is not the right way to do it, and shouldn't use a
subsubheading for a digression like that. So how do I do it?
Thank you
Daniele Parisi