Help how I do create a UI for my new programing language Ele

Question

Help it should have a color coded text in textarea, number line. Etc or professional looking UI

I don't know Css well
Hence anyone wana help and get Crdits for helping?

Plz help I wana complete this project soon

https://code.sololearn.com/Wsj2lrSdJwiC/?ref=app