How to up my frontpage skills?

I am pretty confident with building websites using Django or Flask. However, when it comes to building the actual HTML I struggle big time. I default to ready-made templates and tweak them as I need. However, I would like to improve, not just by trial and error, but by following best practices.

Coming from a Python background, suddenly you face webpack, grunt, node, npm, yarn... So many things all at once that it is hard to know how to get started.

So, I am looking for resources that can help me speed up my learning process. Especially if there is someone focusing on templates for Django or Jinja2, that would be awesome, but any type of front-page get started tutorial would be great.

As a side note, I would really like to skip Vue, React, etc. for now, since they bring in a level of complexity (also to the back end) which I am not willing to undertake at the moment, maybe later on.