Hi Gerald,
As you said It’s nice and simple - in my opinion that’s the way how technical documentation should look like.
I don’t think however your layout is user friendly in mobile size.
I’d rather place your nav section above body as “hamburger” style menu - there is a lot of tutorials online how to create one. You can do it with a little JS or only with CSS.
I haven’t finished my documentation yet, but I’m really close. Probably I’ll put it online today