To be fair to the software, it is not actually that bad, of course it has some quirks, and the underlying phylosophy is largely utterly wrong, but the software in itself works.
BUT it is essentialy a white canvas where everyone can draw whatever he/she wants, the defaults are “terrible”, but the real issue is that in all these years noone with a minimum of good taste, knowledge of colour spaces and contrast put together something at the same time working and pleasing to the eye (or if someone did it was never shared or I couldn’t find it).
With the Solarized theme:
AND the CSS mods by Teslasystems:
it is actually bearable, still far from perfect, but not bad at all.
I haven’t re-tested on newer browsers if now the Solarized theme holds (it did initially, then - for some reasons - it didn’t take anymore).
I have an instance of Palemoon where it works, and it is not that bad.
In its default whitish theme it is unusable, I have a couple devices where it was bearable using the dark themes (but currently the new “change colour of topic starter posts” has made it unreadable in most cases, hopefully this will soon be fixed as well as the Solarized theme).