Where did the main.css file come from in the Node.js Tutorials: Building a Static Site 5 video?

Question

css

Didn't work with git. I am just starting to learn the language. I'm watching the video: youtu.be/Rg__BkSmoHo Actually the question is, where did he get the main.css file from? It's about 3 to 4 minutes. I made a website based on video, everything worked out up to this point.

Answer 1

from the video you can see that the dude created the main.styl file, which was then converted to css.

Answer 2

Tell me how?