I never really understood why people had such difficulty with this. I was able to execute table-less layouts while still supporting IE5 on Mac.
> To this day, changing a site's entire design without touching its markup is a mirage.
That's only because HTML authoring is dead. No one writes HTML well these days. Just look at tools like Elementor. How many nested divs do you need to add a faux button to a website? It's ridiculous.
Write well-structured, semantic HTML being mindful of a separation of concerns, and flipping between stylesheets is a piece of cake.