I actually really like the black black. And they didn't use red red (assuming that term is supposed to mean FF0000); it's quite a dull red, which I find works quite well. I prefer the high contrast mode though, with white white on black black, rather than slightly lower-contrast light grey text. I'm told it's apparently evidence-based to use the lower-contrast version, but it doesn't appeal to me.

Though I will say I intensely dislike the use of underline styling on "WRONG". Underline, on the web, has universally come to be a signal of a hyperlink, and should almost never be used otherwise. It also uses some much nicer colours for both unclicked and visited hyperlinks.