They have used an umlaut on the second repeated vowel in a word for as long as I've been reading. I can't find a link but I believe that's part of their style guide
I have done interviews with Karat which just outsources technical interviews to engineers elsewhere.
All of these technical interviews still suck though! I basically never code with someone watching me and find it very difficult to do in interviews. I also find it hard to find the time to actually practice this skill
Lots of people saying they did something similar, so I'll add that I also did something similar for learning / fun(?) with the added wrinkle that it runs on a raspberry pi at my house. I used golang's Fiber to serve the html/css. Fiber comes with some built-in templating as well to help with the layout. https://www.ianmyjer.com/content/homelab.md