The CSS Zen Garden dream finally ships on Firefox.com

The CSS Zen Garden worked because everyone was using a single markup file. In real life, it doesn't really work.

Instead of thinking of separation of concerns as a religious principle, think about what benefits it actually yields in the case of HTML.

When the markup is completely separated from its styling, this means that the CSS rules need a way to be mapped onto the DOM. This involves specific elements, organized a specific way. If anything is out of place in the markup, the properties may not apply as intended. Similarly, if the CSS doesn't account for DOM structures, then you need modify rules or add new ones.

This way of mapping is an implicit structure. It's something extra that's required, beyond the source code that's there. It can be computed by the browser, but it's not explicitly stated for a developer looking at the code to understand.

Contrast this with Tailwind, Tachyons, etc., where nearly all the structure is explicit, less complex, discoverable, and out in the open.

Hidden structure looks nice to the developer. The code "looks" clean. But understanding a code base's implicit structure is ephemeral, and there's inherent technical debt that will need to be repaid later.

Tailwind looks ugly, but there are no hidden abstractions or structures in the code, beyond its easy conventions and a minimal config file.

And, yes, there are ways to make high-abstraction CSS work, say, with a component library of known DOM patterns. But at that point, why not build the style […]

CSS Zen Garden in the era of agentic software development.... I would say we're at a point where if the entire site was developed in tables or CSS or a Rust based engine emitting wasm positioned elements - no one would care anymore.

Just give me a view and let me operate on things. We're going to have our "LCARS" moment soon. Where no one really needs to create a UI - the system creates one for you at time of use - based on what you're looking at and doing. We're no longer going to need UI/UX, everything will adapt to the person using things.

This is really great work, but I think a lot of folks on HN don't look kindly on the CSS Zen Garden or that era of CSS. They think the markup/stylesheet separation of concerns was a terrible idea, an idea that Tailwind exists to fix. (I think they're wrong, that separation of concerns is good, Tailwind is a hack, and get off my lawn while you're at it.)

The point is - now the modern vanilla web platform really can support first-class CSS-styled app components, from design systems, in production. This is really cool!

HTML and CSS were originally designed as document-oriented languages for digital document display; think MS Word or PDF with cross-document hyperlinks, and not an app SDK. The idea was simply "style your web site's titles, headings, paragraphs, footers, etc. in just one place; change it there and the whole site will update". That's the dream that CSS Zen Garden was meant to showcase. Interactivity and web apps came later, and CSS has taken a very long time to catch up.

But catch up it has, and I'll be glad when frontend web development sheds Tailwind and React in favor of the updated vanilla web platform; and I won't complain if we use super light web component libraries like Lit[0]).

[0] https://lit.dev

I see no connection whatsoever with the CSS Zen Garden dream. CSS Zen Garden was about applying radically different styles to the same markup. This is about newer CSS features like Custom Properties, Flex and Grid making maintenance of a single stylesheet for a single completely typical website.