It is unreadable, literally.

The problem is "@media (prefers-color-scheme:dark)". If you're using a dark theme it'll use a light font color but keeping the light background.

I personally hate when a site changes the default look based on how my OS looks.

I prefer it because I want a dark theme everywhere. It’s just a fault in the website if it shows me something unusable.

You're not kidding. This is the most unreadable website I have ever seen. It is absolutely absurd.

May I point out the fact that he is complaining about "UIs that tend to have low contrast/readability"? Unironically?

No contrast issues on firefox on windows. There's more contrast on that webpage than in downvoted comments here.

It looks like it's broken dark mode support.

Sorry, I don't use/didn't test on Firefox. I'll fix that.

I see it unreadable in Firefox, but its actually light text on dark background in Chrome, Safari

For me it depends on whether my system is set to dark mode or light mode.

If it is dark mode, it is light text on a dark background. With light mode, it is reasonably dark text on a light background.

Maybe on Firefox it is taking the light-mode backgroud with the dark-mode text.