Tags: css



Monday, May 23rd, 2022

Min-Max-Value Interpolation

Here’s a really nice little tool inspired by Utopia for generating one-off clamp() values for fluid type or spacing.

Thursday, May 5th, 2022

Tim Brown: CSS forces

Some interesting thoughts from Tim here. What if CSS could “displace” design decisions from one area to another?

For example, a flexible line spacing value in one container could influence margins that surround the text block. That change in spaciousness may mean that nearby headings need size or spacing adjustments to stay feeling connected.

This feels like the complete opposite way that most people approach design systems—modular, componentised, and discrete—but very in-line with the way that CSS has been designed—interconnected, relational and cascading.

Wednesday, May 4th, 2022

Fluid Type Scale - Generate responsive font-size variables

This is kind of a Utopia lite: pop in your minimum and maximum font sizes along with a modular scale and it spits out some custom properties for clamp() declarations.

Contextual Spacing For Intrinsic Web Design | Modern CSS Solutions

To complement her talk at Beyond Tellerrand, Stephanie goes through some of the powerful CSS features that enable intrinsic web design. These are all great tools for the declarative design approach I was talking about:

Tuesday, May 3rd, 2022


A while back I wrote a blog post called Web Audio API weirdness on iOS. I described a bug in Mobile Safari along with a hacky fix. I finished by saying:

If you ever find yourself getting weird but inconsistent behaviour on iOS using the Web Audio API, this nasty little hack could help.

Recently Jonathan Aldrich posted a thread about the same bug. He included a link to my blog post. He also said:

Thanks so much for your post, this was a truly pernicious problem!

That warms the cockles of my heart. It’s very gratifying to know that documenting the bug (and the fix) helped someone out. Or, as I put it:

Yay for bugblogging!

Forgive the Germanic compound word, but in this case I think it fits.

Bugblogging doesn’t need to involve a solution. Just documenting a bug is a good thing to do. Recently I documented a bug with progressive web apps on iOS. Before that I documented a bug in Facebook Container for Firefox. When I documented some weird behaviour with the Web Share API in Safari on iOS, I wasn’t even sure it was a bug but Tess was pretty sure it was and filed a proper bug report.

I’ve benefited from other people bugblogging. Phil Nash wrote Service workers: beware Safari’s range request. That was exactly what I needed to solve a problem I’d been having. And then that post about Phil solving my problem helped Peter Rukavina solve a similar issue so he wrote Phil Nash and Jeremy Keith Save the Safari Video Playback Day.

Again, this warmed the cockles of my heart. Bugblogging is worth doing just for the reward of that feeling.

There’s a similar kind of blog post where, instead of writing about a bug, you write about a particular technique. In one way, this is the opposite of bugblogging because you’re writing about things working exactly as they should. But these posts have a similar feeling to bugblogging because they also result in a warm glow when someone finds them useful.

Here are some recent examples of these kinds of posts—tipblogging?—that I’ve found useful:

All three are very handy tips. Thanks, Eric! Thanks, Rich! Thanks, Stephanie!

Sunday, May 1st, 2022

Trust • Robin Rendle

Robin adds a long-zoom perspective on my recent post:

I am extremely confident that pretty much any HTML I write today will render the same way in 50 years’ time. How confident am I that my CSS will work correctly? Mmmm…70%. Hand-written JavaScript? Way less, maybe 50%. A third-party service I install on a website or link to? 0% confident. Heck, I’m doubtful that any third-party service will survive until next year, let alone 50 years from now.

Thursday, April 28th, 2022


I’ve already had some thoughtful responses to yesterday’s post about trust. I wrapped up my thoughts with a request:

I would love it if someone could explain why they avoid native browser features but use third-party code.

Chris obliged:

I can’t speak for the industry, but I have a guess. Third-party code (like the referenced Bootstrap and React) have a history of smoothing over significant cross-browser issues and providing better-than-browser ergonomic APIs. jQuery was created to smooth over cross-browser JavaScript problems. That’s trust.

Very true! jQuery is the canonical example of a library smoothing over the bumpy landscape of browser compatibilities. But jQuery is also the canonical example of a library we no longer need because the browsers have caught up …and those browsers support standards directly influenced by jQuery. That’s a library success story!

Charles Harries takes on my question in his post Libraries over browser features:

I think this perspective of trust has been hammered into developers over the past maybe like 5 years of JavaScript development based almost exclusively on inequality of browser feature support. Things are looking good in 2022; but as recently as 2019, 4 of the 5 top web developer needs had to do with browser compatibility.

Browser compatibility is one of the underlying promises that libraries—especially the big ones that Jeremy references, like React and Bootstrap—make to developers.

So again, it’s browser incompatibilities that made libraries attractive.

Jim Nielsen responds with the same message in his post Trusting Browsers:

We distrust the browser because we’ve been trained to. Years of fighting browser deficiencies where libraries filled the gaps. Browser enemy; library friend.

For example: jQuery did wonders to normalize working across browsers. Write code once, run it in any browser — confidently.

Three for three. My question has been answered: people gravitated towards libraries because browsers had inconsistent implementations.

I’m deliberately using the past tense there. I think Jim is onto something when he says that we’ve been trained not to trust browsers to have parity when it comes to supporting standards. But that has changed.

Charles again:

This approach isn’t a sustainable practice, and I’m trying to do as little of it as I can. Jeremy is right to be suspicious of third-party code. Cross-browser compatibility has gotten a lot better, and campaigns like Interop 2022 are doing a lot to reduce the burden. It’s getting better, but the exasperated I-just-want-it-to-work mindset is tough to uninstall.

I agree. Inertia is a powerful force. No matter how good cross-browser compatibility gets, it’s going to take a long time for developers to shed their suspicion.

Jim is glass-half-full kind of guy:

I’m optimistic that trust in browser-native features and APIs is being restored.

He also points to a very sensible mindset when it comes to third-party libraries and frameworks:

In this sense, third-party code and abstractions can be wonderful polyfills for the web platform. The idea being that the default posture should be: leverage as much of the web platform as possible, then where there are gaps to creating great user experiences, fill them in with exploratory library or framework features (features which, conceivably, could one day become native in browsers).

Yes! A kind of progressive enhancement approach to using third-party code makes a lot of sense. I’ve always maintained that you should treat libraries and frameworks like cattle, not pets. Don’t get too attached. If the library is solving a genuine need, it will be replaced by stable web standards in browsers (again, see jQuery).

I think that third-party libraries and frameworks work best as polyfills. But the whole point of polyfills is that you only use them when the browsers don’t supply features natively (and you also go back and remove the polyfill later when browsers do support the feature). But that’s not how people are using libraries and frameworks today. Developers are reaching for them by default instead of treating them as a last resort.

I like Jim’s proposed design princple:

Where available, default to browser-native features over third party code, abstractions, or idioms.

(P.S. It’s kind of lovely to see this kind of thoughtful blog-to-blog conversation happening. Right at a time when Twitter is about to go down the tubes, this is a demonstration of an actual public square with more nuanced discussion. Make your own website and join the conversation!)

Wednesday, April 27th, 2022

Flexibly Centering an Element with Side-Aligned Content – Eric’s Archived Thoughts

This is a great little tip from Eric for those situations when you want an element to be centred but you want the content inside that element to remain uncentred:

max-inline-size: max-content;
margin-inline: auto;

And I completely concur with his closing thoughts on CSS today:

It’s a nice little example of the quiet revolution that’s been happening in CSS of late. Hard things are becoming easy, and more than easy, simple. Simple in the sense of “direct and not complex”, not in the sense of “obvious and basic”. There’s a sense of growing maturity in the language, and I’m really happy to see it.


I’ve noticed a strange mindset amongst front-end/full-stack developers. At least it seems strange to me. But maybe I’m the one with the strange mindset and everyone else knows something I don’t.

It’s to do with trust and suspicion.

I’ve made no secret of the fact that I’m suspicious of third-party code and dependencies in general. Every dependency you add to a project is one more potential single point of failure. You have to trust that the strangers who wrote that code knew what they were doing. I’m still somewhat flabbergasted that developers regularly add dependencies—via npm or yarn or whatever—that then pull in even more dependencies, all while assuming good faith and competence on the part of every person involved.

It’s a touching expression of faith in your fellow humans, but I’m not keen on the idea of faith-based development.

I’m much more trusting of native browser features—HTML elements, CSS features, and JavaScript APIs. They’re not always perfect, but a lot of thought goes into their development. By the time they land in browsers, a whole lot of smart people have kicked the tyres and considered many different angles. As a bonus, I don’t need to install them. Even better, end users don’t need to install them.

And yet, the mindset I’ve noticed is that many developers are suspicious of browser features but trusting of third-party libraries.

When I write and talk about using service workers, I often come across scepticism from developers about writing the service worker code. “Is there a library I can use?” they ask. “Well, yes” I reply, “but then you’ve got to understand the library, and the time it takes you to do that could be spent understanding the native code.” So even though a library might not offer any new functionality—just a different idion—many developers are more likely to trust the third-party library than they are to trust the underlying code that the third-party library is abstracting!

Developers are more likely to trust, say, Bootstrap than they are to trust CSS grid or custom properties. Developers are more likely to trust React than they are to trust web components.

On the one hand, I get it. Bootstrap and React are very popular. That popularity speaks volumes. If lots of people use a technology, it must be a safe bet, right?

But if we’re talking about popularity, every single browser today ships with support for features like grid, custom properties, service workers and web components. No third-party framework can even come close to that install base.

And the fact that these technologies have shipped in stable browsers means they’re vetted. They’ve been through a rigourous testing phase. They’ve effectively got a seal of approval from each individual browser maker. To me, that seems like a much bigger signal of trustworthiness than the popularity of a third-party library or framework.

So I’m kind of confused by this prevalent mindset of trusting third-party code more than built-in browser features.

Is it because of the job market? When recruiters are looking for developers, their laundry list is usually third-party technologies: React, Vue, Bootstrap, etc. It’s rare to find a job ad that lists native browser technologies: flexbox, grid, service workers, web components.

I would love it if someone could explain why they avoid native browser features but use third-party code.

Until then, I shall remain perplexed.

Tuesday, April 26th, 2022

Speaking at CSS Day 2022

I’m very excited about speaking at CSS Day this year. My talk is called In And Out Of Style:

It’s an exciting time for CSS! It feels like new features are being added every day. And yet, through it all, CSS has managed to remain an accessible language for anyone making websites. Is this an inevitable part of the design of CSS? Or has CSS been formed by chance? Let’s take a look at the history—and some alternative histories—of the World Wide Web to better understand where we are today. And then, let’s cast our gaze to the future!

Technically, CSS Day won’t be the first outing for this talk but it will be the in-person debut. I had the chance to give the talk online last week at An Event Apart. Giving a talk online isn’t quite the same as speaking on stage, but I got enough feedback from the attendees that I’m feeling confident about giving the talk in Amsterdam. It went down well with the audience at An Event Apart.

If the description has you intrigued, come along to CSS Day to hear the talk in person. And if you like the subject matter, I’ve put together these links to go with the talk…

Blog posts


Proposals (email)

Papers (PDF)

People (Wikipedia)

Tuesday, April 19th, 2022

Upcoming events

I see that Russell is planning to bring back Interesting this year. This makes me happy. Just seeing the return of in-person gatherings—run safely—is giving me life.

I don’t think I’m alone in this. I think that lots of people are yearning for some in-person contact after two years of online events. The good news is that there are some excellent in-person web conferences on the horizon.

Beyond Tellerrand is back in Düsseldorf on May 2nd and 3rd. Marc ran some of the best online events during lockdown with his Stay Curious cafés, but there’s nothing beats the atmosphere of Beyond Tellerrand on its home turf.

If you can’t make it Düsseldorf—I probably can’t because I’m getting my passport renewed right now—there’s All Day Hey in Leeds on May 5th. Harry has put a terrific line-up together for this one-day, very affordable event.

June is shaping up to be a good month for events too. First of all, there’s CSS Day in Amsterdam on June 9th and 10th. I really, really like this event. I’m not just saying that because I’m speaking at this year’s CSS Day. I just love the way that the conference treats CSS with respect. If you self-identigy as a CSS person, then this is the opportunity to be with your people.

But again, if you can’t make it Amsterdam, never fear. The Pixel Pioneers conference returns to Bristol on June 10th. Another one-day event in the UK with a great line-up.

Finally, there’s the big one at the end of June. UX London runs from June 28th to June 30th:

Bringing the UX community back together

Yes, I’m biased because I’m curating the line-up but this is shaping up to be unmissable! It’s going to be so good to gather with our peers and get our brains filled by the finest of design minds.

Be the browser’s mentor, not its micromanager. - Build Excellent Websites

This one-page site that Andy has made to illustrate his talk at All Day Hey is exactly what I was talking about with declarative design.

Give the browser some solid rules and hints, then let it make the right decisions for the people that visit it, based on their device, connection quality and capabilities. This is how they will get a genuinely great user experience, rather than a fragmented, broken one.

Thursday, April 14th, 2022

Declarative design

I feel like in the past few years there’s been a number of web design approaches that share a similar mindset. Intrinsic web design by Jen; Every Layout by Andy and Heydon; Utopia by Trys and James.

To some extent, their strengths lie in technological advances in CSS: flexbox, grid, calc, and so on. But more importantly, they share an approach. They all focus on creating the right inputs rather than trying to control every possible output. Leave the final calculations for those outputs to the browser—that’s what computers are good at.

As Andy puts it:

Be the browser’s mentor, not its micromanager.

Reflecting on Utopia’s approach, Jim Nielsen wrote:

We say CSS is “declarative”, but the more and more I write breakpoints to accommodate all the different ways a design can change across the viewport spectrum, the more I feel like I’m writing imperative code. At what quantity does a set of declarative rules begin to look like imperative instructions?

In contrast, one of the principles of Utopia is to be declarative and “describe what is to be done rather than command how to do it”. This approach declares a set of rules such that you could pick any viewport width and, using a formula, derive what the type size and spacing would be at that size.

Declarative! Maybe that’s the word I’ve been looking for to describe the commonalities between Utopia, Every Layout, and intrinsic web design.

So if declarative design is a thing, does that also mean imperative design is also a thing? And what might the tools and technologies for imperative design look like?

I think that Tailwind might be a good example of an imperative design tool. It’s only about the specific outputs. Systematic thinking is actively discouraged; instead you say exactly what you want the final pixels on the screen to be.

I’m not saying that declarative tools—like Utopia—are right and that imperative tools—like Tailwind—are wrong. As always, it depends. In this case, it depends on the mindset you have.

If you agree with this statement, you should probably use an imperative design tool:

CSS is broken and I want my tools to work around the way CSS has been designed.

But if you agree with this statement, you should probably use a declarative design tool:

CSS is awesome and I want my tools to amplify the way that CSS had been designed.

If you agree with the first statement but you then try using a declarative tool like Utopia or Every Layout, you will probably have a bad time. You’ll probably hate it. You may declare the tool to be “bad”.

Likewise if you agree with the second statement but you then try using an imperative tool like Tailwind, you will probably have a bad time. You’ll probably hate it. You may declare the tool to be “bad”.

It all depends on whether the philosophy behind the tool matches your own philosophy. If those philosophies match up, then using the tool will be productive and that tool will act as an amplifier—a bicycle for the mind. But if the philosophy of the tool doesn’t match your own philosophy, then you will be fighting the tool at every step—it will slow you down.

Knowing that this spectrum exists between declarative tools and imperative tools can help you when you’re evaluating technology. You can assess whether a web design tool is being marketed on the premise that CSS is broken or on the premise that CSS is awesome.

I wonder whether your path into web design and development might also factor into which end of the spectrum you’d identify with. Like, if your background is in declarative languages like HTML and CSS, maybe intrisic web design really resonates. But if your background is in imperative languages like JavaScript, perhaps Tailwind makes more sense to you.

Again, there’s no right or wrong here. This is about matching the right tool to the right mindset.

Personally, the declarative design approach fits me like a glove. It feels like it’s in the tradition of John’s A Dao Of Web Design or Ethan’s Responsive Web Design—ways of working with the grain of the web.

Tuesday, April 12th, 2022

CSS Quick Tip: Animating in a newly added element | Stephanie Eckles

I can see myself almost certainly needing to use this clever technique at some point so I’m going to squirrel it away now for future me.

Thoughts on Exerting Control With Media Queries - Jim Nielsen’s Blog

Some thoughts on CSS, media queries, and fluid type prompted by Utopia:

We say CSS is “declarative”, but the more and more I write breakpoints to accommodate all the different ways a design can change across the viewport spectrum, the more I feel like I’m writing imperative code. At what quantity does a set of declarative rules begin to look like imperative instructions?

In contrast, one of the principles of Utopia is to be declarative and “describe what is to be done rather than command how to do it”. This approach declares a set of rules such that you could pick any viewport width and, using a formula, derive what the type size and spacing would be at that size.

Monday, April 4th, 2022

Understanding Layout Algorithms

Josh is great at explaining tricky concepts and here he’s really set himself a challenge: explaining layout modes in CSS.

Sunday, March 13th, 2022

Make it boring — jlwagner.net

People are propelled by their interests, and web developers have a lot of space to be interested in all sorts of stuff. For you, it may be JavaScript ‘n Friends, or HTML and CSS. Maybe it’s all that stuff, but put aside your preferences for a moment and answer me this: what are you helping people to do? If the answer involves any remotely routine or crucial purpose, consider putting aside your personal desire for excitement. Instead, make boring things that are usable, accessible, and fast. Ours is a job done by people for people, not a glamorous rockstar gig.

Excellent advice from Jeremy who wants us to build fast, reliable, resilient websites …even if the technologies involved in doing that don’t feel exciting.

Central to that endeavor is recognizing that the browser gives you a ton of stuff for free. Relying on those freebies requires a willingness to not npm install a solution for every problem — especially those that are best solved with CSS and HTML. Those technologies may seem boring, but boring is fast. Boring is usable. Boring is resilient and fault tolerant. Boring is accessible. When we rely wholesale on JavaScript to build for the web, we’re inevitably reinventing things. At worst, our reinventions of rock-solid HTML features — such as client-side form validation  — break in unexpected ways despite our carefully written tests. At best, a flawless reimplementation of those features adds unnecessary code to applications, and depends on a technology less fault-tolerant than CSS and HTML.

Monday, March 7th, 2022

web-platform-tests dashboard

It’s great to see browsers working together to collectively implement a range of much-needed features.

These scores represent how browser engines are doing in 15 focus areas and 3 joint investigation efforts.

Saturday, March 5th, 2022

Utopia - an introduction - YouTube

James and Trys have made this terrific explanatory video about Utopia. They pack a lot into less than twenty minutes but it’s all very clearly and methodically explained.

Utopia - an introduction

Progressive Enhancement, the New Hotness™ | Go Make Things

Here’s a great explanation of progressive enhancement, complete with practical examples and myth-busting. Pass it ‘round!

If you care about quality engineering, you want as much fault tolerance in the things you build as possible.