Yeah… My focus is mostly on readability, with little tweaks here and there… Didn’t want to change the default layout since many people are already used to it, and actually it’s not that bad imo…
And thanks for the heads-up, I’ll give stylus a shot next time…
TBH I think the default layout, at least on desktop view, is pretty bad on most pages.
The actual posts aren’t too bad, and are easy to tweak, but the home page does my head in. There’s no way I would want to use that, and thanks to the magic of custom CSS I don’t have to. 
The topic index pages are basically a gigantic waste of space in boards that have topic thumbs, so I’ve recoded those to have smaller thumbs that expand on hover for desktop, and on click for touchscreen. IMO it makes the whole page much more compact and easy to scan.
I’m also thinking the Discourse oh-hai-we-borked-ur-scrollbar-with-our-gizmo “feature” could usefully be whacked over to the right, next to the browser scrollbar, and given a decent size to match. I still find myself automatically going for the browser scrollbar and then thinking “Oh, bugger”.
If the Discourse nefarious mongrel thingy was stuck over there anyway, and big enough to hit with brain in neutral, this would probably be better usability all round. It would also save some nasty little coding problems with varying screen sizes. The default media queries are a tad ludicrous IMO.
@TheRedWaxPolice Holy crap, with this, the forum looks a lot more clean and easy to read. Love it. 
@bartv I guess this is it, right? This one as the default dark theme and your tweaked white theme as the default light theme. How about that?
@Gumboots I was using Stylish too. Thanks for the hint.