How to make the Reading View to look like the help docs?

First off, the help docs are drop-dead gorgeous!!! I love the design and the way the pages look. Although I do not have the money for it today but one day I will definitely publish my notes.

What I’m trying to do

I want my notes (especially when in reading view) to look like the help docs since they are absolutely gorgeous not going to lie. Is that attainable without HTML, community plugins or community themes? I do not want to download anything community since certain things I keep in the vault are confidential & stored temporarily until they are released from the vault. Custom CSS is perfectly fine.

Things I have tried

I have tried using --- to create line separation like they do on the site but I have failed – it looks bland and the spacing is so bad it makes any reader’s eyes bleed – which is also why I am not going to show screenshots here.

I have also tried looking at custom CSS but nothing has worked (or maybe I am not a very good CSS coder, more into Python and JS)