Page-owned shell
Header on top, main in the middle, footer at the bottom.
The root keeps the document skeleton. This route owns the visible structure, so the holy grail pattern stays local to the page instead of leaking into the app shell.
Nested header
Header, main, footer inside the article.
The nested shell lets the middle track adapt to the article width instead of the viewport.
Main
The middle track expands and remains readable at every width.