[css] reduce spacing around admonitions

[sneakers-the-rat]

It looks like my reduction of the spacing around admonitions got removed here? 75e89a8

Not sure if this was on purpose or not, i know there has been a lot of rapid change in this repo lately :). I think Leah and I in general have different tastes in layout, which is totally fine, so i'm just checking, close this if it was on purpose.

Currently the margins are fixed size (60px/70px), which to my eyes is a lot. The admonitions are already visually offset being in boxes, and the other dom elements like sections and headers also already have their own margins, and so with this amount of spacing they (imo) disrupt the flow of text enough to warrant change. I think it's especially obvious on mobile:

between headings	in text

So this PR does:

between headings	in text

[lwasser]

oops @sneakers-the-rat yes we do have different tastes!! And that is totally ok.

I should have overcommunicated about what i did.
Id like to adding custom css to our pyos-sphinx-theme template rather than have different styles in each repo.

right now that theme won't build - i haven't had time to troubleshoot the build issues but am open to pr's or fixes there. Then we could talk about new styles in one place and apply them in one place. Are you ok with that?

i think we could find a middle ground here easily where the admonition spacing is a bit less but maybe more than you made it in the previous PR?

but what i really want to do is APOLOGIZE for not communicating about that to you. I've just been so focused on things. i greatly appreciate how much you think about presentation! And there is always a middle ground i think!! so i'm sorry.

Please let me know how that lands!!

[sneakers-the-rat]

o ya, totally fine. i was just making css changes here because i figured we didn't want to fuss with versions of the theme package and could collect them later.

no big deal, we can tweak it over there some other time :)