I have added the two new themes created by https://lemmy.ml/u/armoredgore
You can load them by going to your settings page and setting the theme to “winternord” or “mintybubble”
They are quite cool, so please check them out!
Here are the relevant posts:
Lemmy-ui has potential
needs moar black and red! (just kidding, because all my sites are themed black and red)
You are right! Black and read is a nice combination! I will try to make one when I get the chance ;)