There is no stylesheet on this page. There is no script tag, no font file, no icon set, no build step, no framework, no hydration pass, and nothing waiting on a third-party CDN before you can read a sentence. Every size, margin, and colour you are looking at was chosen by your browser roughly thirty years ago and has worked in every browser released since. Here is what that buys you:
Most of the weight on a modern page is not content. It is the machinery added to present content that would have been fine on its own. A hover animation on a badge nobody clicks costs real kilobytes and real milliseconds, and someone poking at it on a phone will never trigger it. Someone using a screen reader will never encounter it at all. The page below has none of that machinery, and it still tells you everything it set out to tell you, which is the whole argument.
You already knew this. Here is the demonstration anyway.
This entire document is smaller than a single logo on an average marketing page. No jQuery loaded to fade a background colour. No seven weights of a webfont pulled down so one heading can say hello at a hundred pixels tall. The transfer is the markup and nothing else, which means the time to first meaningful paint is however long your connection takes to move a few thousand bytes.
Not because of breakpoints. Because a block-level element with no width set fills whatever space it is given, and text wraps. That is the default behaviour of the medium. Responsive design was the process of getting back to it after we had spent a decade fighting it with fixed pixel layouts.
You can read it. It makes sense. It has hierarchy, expressed with the elements that mean hierarchy, so your browser, your reader mode, your screen reader, and any parser written in the next twenty years all agree on what is a heading and what is a paragraph. That is what semantics are for, and they cost nothing.
There is content on the screen right now. Not spread over seven full-height panels behind a bouncing arrow, not revealed on scroll, not held back until an observer fires. It was there when the document arrived.
Cross-browser compatibility? Open it in anything. Genuinely, anything.
Strip away the shadows, the gradients, the parallax and the loading states, and what is left is text communicating a message, marked up so a machine can understand its shape. That is the base state of the web. Everything else is an addition, and additions should have to justify themselves. This page is the unadorned version. It is not ugly. It is unfinished only if you assume finishing means adding.
Nobody is claiming your site should ship without a stylesheet. The point is narrower and harder to dodge: pages are fast, accessible, and robust when they arrive, and every problem after that is one we introduce ourselves. Nothing here broke, because nothing here was added.
"Good design is as little design as possible."
- Dieter Rams