Excessive padding in some cases (bikeshedding)

[KristofferC]

I feel that the padding used in some elements in the default style is a bit excessive and makes these element take up a lot of vertical space.

Admonitions

Looking at e.g. the docs for Python https://docs.python.org/3/whatsnew/3.10.html and adopting that (7px) would give:

Code blocks

Going from 0.7 to 0.3 in the padding gives something like:

[mortenpi]

I can get behind reducing the padding in the admonitions for sure. It would also be nice if the left-padding of the content would align with the title. I am not sure I like making the padding this narrow though. Let me make a PR in the next week to bikeshed this a little further.