Hi, I've never encountered something like this. I was able to replicate it as well and I just posted an updated version which doesn't support dark mode, so everything should look like in screenshots. Thanks for reporting this!
Edit: For anyone curious why this happened. I used Vite for creating React app and by default it included CSS with support for light and dark modes, but since I changed some CSS styles but didn't update the light/dark mode styles that's why it looked broken when switched to dark mode.