I don't entirely get what you mean by "layout engine". A WYSIWYG editor perhaps? Or maybe a canvas like Microsoft OneNote, where you can draw and put text boxes? Or a word processor? Why isn't the usual Markdown (or the like) approach enough?
My gut feeling is that you cannot (fully) abstract away HTML/CSS if you want the result to feel like an actual website.
With Astro, MkDocs or docfx, I do not have to touch HTML, except maybe for creating the master layout and/or transformation rules, if needed.
> Why isn't the usual Markdown (or the like) approach enough?
Because you can't use markdown to design CSS or SVG animations. I want to be able to design an animation with code that describes how the elements move/interact and then compile that down into CSS or SVG keyframes so that I don't have to manually declare however many arbitrarily complex keyframes.
I understand the purpose of a static site generator and I'm not looking for anything to replace that. Rather I want to be able to write the templates for my static sites without 1. writing exceptionally tedious HTML & CSS and without 2. relying on client side JS to do those tedious things.
My gut feeling is that you cannot (fully) abstract away HTML/CSS if you want the result to feel like an actual website.
With Astro, MkDocs or docfx, I do not have to touch HTML, except maybe for creating the master layout and/or transformation rules, if needed.