How we make RWD sites load fast as heck

Scott shares the code that Filament Group are using to determine which style declarations are critical (and can be inlined) and which are non-critical (and can be loaded asynchronously). It makes quite a difference in perceived performance.

By the way, I really, really like the terminology of “critical” and “non-critical” CSS, rather than “above the fold” and “below the fold” CSS.

How we make RWD sites load fast as heck

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It’s time for modern CSS to kill the SPA - Jono Alderson

SPAs were a clever solution to a temporary limitation. But that limitation no longer exists.

Use modern server rendering. Use actual pages. Animate with CSS. Preload with intent. Ship less JavaScript.

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I’m more proud of these 128 kilobytes than anything I’ve built since | by Mike Hall | Jul, 2025 | Medium

I don’t normally link to articles on Medium—I respect you too much—and I do wish this were written on Mike Hall’s own site, but this is just too good not to share.

And don’t dismiss this as a nostalgiac case study from the past:

At no point did the constraints make the product feel compromised. Users on modern devices got a smooth experience and instant feedback, while those on older devices got fast, reliable functionality. Users on feature phones got the same core experience without the bells and whistles.

The constraints forced us to solve problems in ways we wouldn’t have considered otherwise. Without those constraints, we could have just thrown bytes at the problem, but with them every feature had to justify itself. Core functionality had to work everywhere, and without JavaScript crutches proper markup became essential.

This experience changed how I approach design problems. Constraints aren’t a straitjacket, keeping us from doing our best work; they are the foundation that makes innovation possible. When you have to work within severe limitations, you find elegant solutions that scale beyond those limitations.

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I wasted a day on CSS selector performance to make a website load 2ms faster | Trys Mudford

Picture me holding Trys back and telling him, “Leave it alone, mate, it’s not worth it!”

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On Container Queries, Responsive Images, and JPEG-XL – Cloud Four

Container queries can’t be used in the sizes attribute for responsive images. Here, Jason breaks down why that is (spoiler: it’s the lookahead pre-parser) and segues into a truly long term solution: a “magical” image format.

If you’ve ever thought it felt weird to put media conditions inside the HTML for responsive images, this will resonate.

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Patrick / articles / Is the developer experience on the Web so terrible?

Over the past 10 years or so, we’ve slowly but very surely transitioned to a state where frameworks are the norm, and I think it’s a problem.

I concur.

Use the frameworks and libraries that make sense for you to deliver the best UX possible. But also learn the web platform from the ground up. Take time to understand how web browsers work and render webpages. Learn HTML, CSS, JavaScript. And keep an eye, if you can, on the new things.

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