Honestly, I wish there was a setting/option to give the whole site a more “professional” theme & feel to it. I’m here to learn and reinforce a language; I don’t care at all for the art and color palette that looks like it belongs in a preschool.
I use @valeth’s [Userstyle] WaniKani Breeze Dark, but every time there’s a change to the site, someone has to go and patch the custom theme because WK doesn’t have its own dark (or even just neutral) theme available.
Edit: As of the time of this post, the author of this theme/style is updating and maintaining it 