The style is called "NeuBrutalism"
I still did not made the dark mode but i plan to! It will require me some more work I think since dark mode is harder to make look good, IMO, and i am also not a designer
Edit: spelling
- It was that one, not a TUI though: https://owickstrom.github.io/the-monospace-web/
- another one, DOS/TUI style: https://github.com/vinibiavatti1/TuiCss