Journal tags: design,principles



Principles and the English language

I work with words. Sometimes they’re my words. Sometimes they’re words that my colleagues have written:

One of my roles at Clearleft is “content buddy.” If anyone is writing a talk, or a blog post, or a proposal and they want an extra pair of eyes on it, I’m there to help.

I also work with web technologies, usually front-of-the-front-end stuff. HTML, CSS, and JavaScript. The technologies that users experience directly in web browsers.

I think a lot about design principles for the web. The two principles I keep coming back to are the robustness principle and the principle of least power.

When it comes to words, the guide that I return to again and again is George Orwell, specifically his short essay, Politics and the English Language.

Towards the end, he offers some rules for writing.

  1. Never use a metaphor, simile, or other figure of speech which you are used to seeing in print.
  2. Never use a long word where a short one will do.
  3. If it is possible to cut a word out, always cut it out.
  4. Never use the passive where you can use the active.
  5. Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent.
  6. Break any of these rules sooner than say anything outright barbarous.

These look a lot like design principles. Not only that, but some of them look like specific design principles. Take the robustness principle:

Be conservative in what you send, be liberal in what you accept.

That first part applies to Orwell’s third rule:

If it is possible to cut a word out, always cut it out.

Be conservative in what words you send.

Then there’s the principle of least power:

Choose the least powerful language suitable for a given purpose.

Compare that to Orwell’s second rule:

Never use a long word where a short one will do.

That could be rephrased as:

Choose the shortest word suitable for a given purpose.

Or, going in the other direction, the principle of least power could be rephrased in Orwell’s terms as:

Never use a powerful language where a simple language will do.

Oh, I like that! I like that a lot.

Mind the gap

In May 2012, Brian LeRoux, the creator of PhoneGap, wrote a post setting out the beliefs, goals and philosophy of the project.

The beliefs are the assumptions that inform everything else. Brian stated two core tenets:

  1. The web solved cross platform.
  2. All technology deprecates with time.

That second belief then informed one of the goals of the PhoneGap project:

The ultimate purpose of PhoneGap is to cease to exist.

Last week, PhoneGap succeeded in its goal:

Since the project’s beginning in 2008, the market has evolved and Progressive Web Apps (PWAs) now bring the power of native apps to web applications.

Today, we are announcing the end of development for PhoneGap.

I think Brian was spot-on with his belief that all technology deprecates with time. I also think it was very astute of him to tie the goals of PhoneGap to that belief. Heck, it’s even in the project name: PhoneGap!

I recently wrote this about Sass and clamp:

I’ve said it before and I’ll say it again, the goal of any good library should be to get so successful as to make itself redundant. That is, the ideas and functionality provided by the tool are so useful and widely adopted that the native technologies—HTML, CSS, and JavaScript—take their cue from those tools.

jQuery is the perfect example of this. jQuery is no longer needed because cross-browser DOM Scripting is now much easier …thanks to jQuery.

Successful libraries and frameworks point the way. They show what developers are yearning for, and that’s where web standards efforts can then focus. When a library or framework is no longer needed, that’s not something to mourn; it’s something to celebrate.

That’s particularly true if the library of code needs to be run by a web browser. The user pays a tax with that extra download so that the developer gets the benefit of the library. When web browsers no longer need the library in order to provide the same functionality, it’s a win for users.

In fact, if you’re providing a front-end library or framework, I believe you should be actively working towards making it obselete. Think of your project as a polyfill. If it’s solving a genuine need, then you should be looking forward to the day when your code is made redundant by web browsers.

One more thing…

I think it was great that Brian documented PhoneGap’s beliefs, goals and philosophy. This is exactly why design principles can be so useful—to clearly set out the priorities of a project, so that there’s no misunderstanding or mixed signals.

If you’re working on a project, take the time to ask yourself what assumptions and beliefs are underpinning the work. Then figure out how those beliefs influence what you prioritise.

Ultimately, the code you produce is the output generated by your priorities. And your priorities are driven by your purpose.

You can make those priorities tangible in the form of design principles.

You can make those design principles visible by publishing them.

Putting design principles into action

I was really looking forward to speaking at An Event Apart this year. I was going to be on the line-up for Seattle, Boston, and Minneapolis; three cities I really like.

At the start of the year, I decided to get a head-start on my new talk so I wouldn’t be too stressed out when the first event approached. I spent most of January and February going through the chaotic process of assembling a semi-coherent presentation out of a katamari of vague thoughts.

I was making good progress. Then The Situation happened. One by one, the in-person editions of An Event Apart were cancelled (quite rightly). But my talk preparation hasn’t been in vain. I’ll be presenting my talk at an online edition of An Event Apart on Monday, August 17th.

You should attend. Not for my talk, but for Ire’s talk on Future-Proof CSS which sounds like it was made for me:

In this talk, we’ll cover how to write CSS that stands the test of time. From progressive enhancement techniques to accessibility considerations, we’ll learn how to write CSS for 100 years in the future (and, of course, today).

My talk will be about design principles …kinda. As usual, it will be quite a rambling affair. At this point I almost take pride in evoking a reaction of “where’s he going with this?” during the first ten minutes of a talk.

When I do actually get around to the point of the talk—design principles—I ask whether it’s possible to have such a thing as universal principles. After all, the whole point of design principles is that they’re specific to an endeavour, whether that’s a company, an organisation, or a product.

I think that some principles are, if not universal, then at least very widely applicable. I’ve written before about two of my favourites: the robustness principle and the principle of least power:

There’s no shortage of principles, laws, and rules out there, and I find many of them very useful, but if I had to pick just two that are particularly applicable to my work, they would be the robustness principle and the rule of least of power.

What’s interesting about both of those principles is that they are imperative. They tell you how to act:

Be conservative in what you send, be liberal in what you accept.

Choose the least powerful language suitable for a given purpose.

Other princples are imperative, but they tell you what not to do. Take the razors of Occam and Hanlon, for example:

Entities are not to be multiplied without necessity.

Never attribute to malice that which is adequately explained by stupidity.

But these imperative principles are exceptions. The vast majority of “universal” principles take the form of laws that are observations. They describe the state of the world without providing any actions to take.

There’s Hofstadter’s Law, for example:

It always takes longer than you expect, even when you take into account Hofstadter’s Law.

Or Clarke’s third law:

Any sufficiently advanced technology is indistinguishable from magic.

By themselves, these observational laws are interesting but they leave it up to you to decide on a course of action. On the other hand, imperative principles tell you what to do but don’t tell you why.

It strikes me that it could be fun (and useful) to pair up observational and imperative principles:

Because of observation A, apply action B.

For example:

Because of Murphy’s Law, apply the principle of least power.

Or in its full form:

Because anything that can go wrong will go wrong, choose the least powerful language suitable for a given purpose.

I feel like the Jevons paradox is another observational principle that should inform our work on the web:

The Jevons paradox occurs when technological progress increases the efficiency with which a resource is used, but the rate of consumption of that resource rises because of increasing demand.

For example, even though devices, browsers, and networks are much, much better now than they were, say, ten years ago, that doesn’t mean that websites have become better or faster. Instead, it’s precisely because there’s more power available that people think nothing of throwing megabytes of JavaScript at users. See Scott’s theory that 5G Will Definitely Make the Web Slower, Maybe:

JavaScript size has ballooned as networks have improved.

This problem would be addressed if web developers were more conservative in what they sent. The robustness principle in action.

Because of the Jevons paradox, apply the robustness principle.

Admittedly, the expanded version of that is far too verbose:

Because technological progress increases the efficiency with which a resource is used, but the rate of consumption of that resource rises because of increasing demand, be conservative in what you send, be liberal in what you accept.

I’m sure there are more and better pairings to be made: an observational principle to tell you why you should take action, and an imperative principle to tell you what action you should take.

Principles and priorities

I think about design principles a lot. I’m such a nerd for design principles, I even have a collection. I’m not saying all of the design principles in the collection are good—far from it! I collect them without judgement.

As for what makes a good design principle, I’ve written about that before. One aspect that everyone seems to agree on is that a design principle shouldn’t be an obvious truism. Take this as an example:

Make it usable.

Who’s going to disagree with that? It’s so agreeable that it’s practically worthless as a design principle. But now take this statement:

Usability is more important than profitability.

Ooh, now we’re talking! That’s controversial. That’s bound to surface some disagreement, which is a good thing. It’s now passing the reversability test—it’s not hard to imagine an endeavour driven by the opposite:

Profitability is more important than usability.

In either formulation, what makes these statements better than the bland toothless agreeable statements—“Usability is good!”, “Profitability is good!”—is that they introduce the element of prioritisation.

I like design principles that can be formulated as:

X, even over Y.

It’s not saying that Y is unimportant, just that X is more important:

Usability, even over profitability.


Profitability, even over usability.

Design principles formulated this way help to crystalise priorities. Chris has written about the importance of establishing—and revisiting—priorities on any project:

Prioritisation isn’t and shouldn’t be a one-off exercise. The changing needs of your customers, the business environment and new opportunities from technology mean prioritisation is best done as a regular activity.

I’ve said it many times, but one on my favourite design principles comes from the HTML design principles. The priority of consitituencies (it’s got “priorities” right there in the name!):

In case of conflict, consider users over authors over implementors over specifiers over theoretical purity.

Or put another way:

  • Users, even over authors.
  • Authors, even over implementors.
  • Implementors, even over specifiers.
  • Specifiers, even over theoretical purity.

When it comes to evaluating technology for the web, I think there are a number of factors at play.

First and foremost, there’s the end user. If a technology choice harms the end user, avoid it. I’m thinking here of the kind of performance tax that a user has to pay when developers choose to use megabytes of JavaScript.

Mind you, some technologies have no direct effect on the end user. When it comes to build tools, version control, toolchains …all the stuff that sits on your computer and never directly interacts with users. In that situation, the wants and needs of developers can absolutely take priority.

But as a general principle, I think this works:

User experience, even over developer experience.

Sadly, I think the current state of “modern” web development reverses that principle. Developer efficiency is prized above all else. Like I said, that would be absolutely fine if we’re talking about technologies that only developers are exposed to, but as soon as we’re talking about shipping those technologies over the network to end users, it’s negligent to continue to prioritise the developer experience.

I feel like personal websites are an exception here. What you do on your own website is completely up to you. But once you’re taking a paycheck to make websites that will be used by other people, it’s incumbent on you to realise that it’s not about you.

I’ve been talking about developers here, but this is something that applies just as much to designers. But I feel like designers go through that priority shift fairly early in their career. At the outset, they’re eager to make their mark and prove themselves. As they grow and realise that it’s not about them, they understand that the most appropriate solution for the user is what matters, even if that’s a “boring” tried-and-tested pattern that isn’t going to wow any fellow designers.

I’d like to think that developers would follow a similar progression, and I’m sure that some do. But I’ve seen many senior developers who have grown more enamoured with technologies instead of honing in on the most appropriate technology for end users. Maybe that’s because in many organisations, developers are positioned further away from the end users (whereas designers are ideally being confronted with their creations being used by actual people). If a lead developer is focused on the productivity, efficiency, and happiness of the dev team, it’s no wonder that their priorities end up overtaking the user experience.

I realise I’m talking in very binary terms here: developer experience versus user experience. I know it’s not always that simple. Other priorities also come into play, like business needs. Sometimes business needs are in direct conflict with user needs. If an online business makes its money through invasive tracking and surveillance, then there’s no point in having a design principle that claims to prioritise user needs above all else. That would be a hollow claim, and the design principle would become worthless.

Because that’s the point with design principles. They’re there to be used. They’re not a nice fluffy exercise in feeling good about your work. The priority of constituencies begins, “in case of conflict” and that’s exactly when a design principle matters—when it’s tested.

Suppose someone with a lot of clout in your organisation makes a decision, but that decision conflicts with your organisations’s design principles. Instead of having an opinion-based argument about who’s right or wrong, the previously agreed-upon design principles allow you to take ego out of the equation.

Prioritisation isn’t easy, and it gets harder the more factors come into play: user needs, business needs, technical constraints. But it’s worth investing the time to get agreement on the priority of your constituencies. And then formulate that agreement into design principles.


I like good design principles. I collect design principles—of varying quality—at Ben Brignell also has a (much larger) collection at

You can spot the less useful design principles after a while. They tend to be wishy-washy; more like empty aspirational exhortations than genuinely useful guidelines for alignment. I’ve written about what makes for good design principles before. Matthew Ström also asked—and answered—What makes a good design principle?

  • Good design principles are memorable.
  • Good design principles help you say no.
  • Good design principles aren’t truisms.
  • Good design principles are applicable.

I like those. They’re like design principles for design principles.

One set of design principles that I’ve included in my collection is from government design principles . I think they’re very well thought-through (although I’m always suspicious when I see a nice even number like 10 for the amount of items in the list). There’s a great line in design principle number two—Do less:

Government should only do what only government can do.

This wasn’t a theoretical issue. The multiple departmental websites that preceded were notorious for having too much irrelevant content—content that was readily available elsewhere. It was downright wasteful to duplicate that content on a government site. It wasn’t appropriate.

Appropriateness is something I keep coming back to when it comes to evaluating web technologies. I don’t think there are good tools and bad tools; just tools that are appropriate or inapropriate for the task at hand. Whether it’s task runners or JavaScript frameworks, appropriateness feels like it should be the deciding factor.

I think that the design principle from GDS could be abstracted into a general technology principle:

Any particular technology should only do what only that particular technology can do.

Take JavaScript, for example. It feels “wrong” when a powerful client-side JavaScript framework is applied to something that could be accomplished using HTML. Making a blog that’s a single page app is over-engineering. It violates this principle:

JavaScript should only do what only JavaScript can do.

Need to manage state or immediately update the interface in response to user action? Only JavaScript can do that. But if you need to present the user with some static content, JavaScript can do that …but it’s not the only technology that can do that. HTML would be more appropriate.

I realise that this is basically a reformulation of one of my favourite design principles, the rule of least power:

Choose the least powerful language suitable for a given purpose.

Or, as Derek put it:

In the web front-end stack — HTML, CSS, JS, and ARIA — if you can solve a problem with a simpler solution lower in the stack, you should. It’s less fragile, more foolproof, and just works.

ARIA should only do what only ARIA can do.

JavaScript should only do what only JavaScript can do.

CSS should only do what only CSS can do.

HTML should only do what only HTML can do.

Robustness and least power

There’s a great article by Steven Garrity over on A List Apart called Design with Difficult Data. It runs through the advantages of using unusual content to stress-test interfaces, referencing Postel’s Law, AKA the robustness principle:

Be conservative in what you send, be liberal in what you accept.

Even though the robustness principle was formulated for packet-switching, I see it at work in all sorts of disciplines, including design. A good example is in best practices for designing forms:

Every field you ask users to fill out requires some effort. The more effort is needed to fill out a form, the less likely users will complete the form. That’s why the foundational rule of form design is shorter is better — get rid of all inessential fields.

In other words, be conservative in the number of form fields you send to users. But then, when it comes to users filling in those fields:

It’s very common for a few variations of an answer to a question to be possible; for example, when a form asks users to provide information about their state, and a user responds by typing their state’s abbreviation instead of the full name (for example, CA instead of California). The form should accept both formats, and it’s the developer job to convert the data into a consistent format.

In other words, be liberal in what you accept from users.

I find the robustness principle to be an immensely powerful way of figuring out how to approach many design problems. When it comes to figuring out what specific tools or technologies to use, there’s an equally useful principle: the rule of least power:

Choose the least powerful language suitable for a given purpose.

On the face of it, this sounds counter-intuitive; why forego a powerful technology in favour of something less powerful?

Well, power comes with a price. Powerful technologies tend to be more complex, which means they can be trickier to use and trickier to swap out later.

Take the front-end stack, for example: HTML, CSS, and JavaScript. HTML and CSS are declarative, so you don’t get as much precise control as you get with an imperative language like JavaScript. But JavaScript comes with a steeper learning curve and a stricter error-handling model than HTML or CSS.

As a general rule, it’s always worth asking if you can accomplish something with a less powerful technology:

In the web front-end stack — HTML, CSS, JS, and ARIA — if you can solve a problem with a simpler solution lower in the stack, you should. It’s less fragile, more foolproof, and just works.

  • Instead of using JavaScript to do animation, see if you can do it in CSS instead.
  • Instead of using JavaScript to do simple client-side form validation, try to use HTML input types and attributes like required.
  • Instead of using ARIA to give a certain role value to a div or span, try to use a more suitable HTML element instead.

It sounds a lot like the KISS principle: Keep It Simple, Stupid. But whereas the KISS principle can be applied within a specific technology—like keeping your CSS manageable—the rule of least power is all about evaluating technology; choosing the most appropriate technology for the task at hand.

There are some associated principles, like YAGNI: You Ain’t Gonna Need It. That helps you avoid picking a technology that’s too powerful for your current needs, but which might be suitable in the future: premature optimisation. Or, as Rachel put it, stop solving problems you don’t yet have:

So make sure every bit of code added to your project is there for a reason you can explain, not just because it is part of some standard toolkit or boilerplate.

There’s no shortage of principles, laws, and rules out there, and I find many of them very useful, but if I had to pick just two that are particularly applicable to my work, they would be the robustness principle and the rule of least of power.

After all, if they’re good enough for Tim Berners-Lee…

Needs must

I got a follow-up comment to my follow-up post about the follow-up comment I got on my original post about Google Analytics. Keep up.

I made the point that, from a front-end performance perspective, server logs have no impact whereas a JavaScript-based analytics solution must have some impact on the end user. Paul Anthony says:

Google won the analytics war because dropping one line of JS in the footer and handing a tried and tested interface to customers is an obvious no brainer in comparison to setting up an open source option that needs a cron job to parse the files, a database to store the results and doesn’t provide mobile interface.

Good point. Dropping one snippet of JavaScript into your front-end codebase is certainly an easier solution …easier for you, that is. The cost is passed on to your users. This is a classic example of where user needs and developer needs are in opposition. I’ve said it before and I’ll say it again:

Given the choice between making something my problem, and making something the user’s problem, I’ll choose to make it my problem every time.

It’s true that this often means doing more work. That’s why it’s called work. This is literally what our jobs are supposed to entail: we put in the work to make life easier for users. We’re supposed to be saving them time, not passing it along.

The example of Google Analytics is pretty extreme, I’ll grant you. The cost to the user of adding that snippet of JavaScript—if you’ve configured things reasonably well—is pretty small (again, just from a performance perspective; there’s still the cost of allowing Google to track them across domains), and the cost to you of setting up a comparable analytics system based on server logs can indeed be disproportionately high. But this tension between user needs and developer needs is something I see play out again and again.

I’ve often thought the HTML design principle called the priority of constituencies could be adopted by web developers:

In case of conflict, consider users over authors over implementors over specifiers over theoretical purity. In other words costs or difficulties to the user should be given more weight than costs to authors.

In Resilient Web Design, I documented the three-step approach I take when I’m building anything on the web:

  1. Identify core functionality.
  2. Make that functionality available using the simplest possible technology.
  3. Enhance!

Now I’m wondering if I should’ve clarified that second step further. When I talk about choosing “the simplest possible technology”, what I mean is “the simplest possible technology for the user”, not “the simplest possible technology for the developer.”

For example, suppose I were going to build a news website. The core functionality is fairly easy to identify: providing the news. Next comes the step where I choose the simplest possible technology. Now, if I were a developer who had plenty of experience building JavaScript-driven single page apps, I might conclude that the simplest route for me would be to render the news via JavaScript. But that would be a fragile starting point if I’m trying to reach as many people as possible (I might well end up building a swishy JavaScript-driven single page app in step three, but step two should almost certainly be good ol’ HTML).

Time and time again, I see decisions that favour developer convenience over user needs. Don’t get me wrong—as a developer, I absolutely want developer convenience …but not at the expense of user needs.

I know that “empathy” is an over-used word in the world of user experience and design, but with good reason. I think we should try to remind ourselves of why we make our architectural decisions by invoking who those decisions benefit. For example, “This tech stack is best option for our team”, or “This solution is the best for the widest range of users.” Then, given the choice, favour user needs in the decision-making process.

There will always be situations where, given time and budget constraints, we end up choosing solutions that are easier for us, but not the best for our users. And that’s okay, as long as we acknowledge that compromise and strive to do better next time.

But when the best solutions for us as developers become enshrined as the best possible solutions, then we are failing the people we serve.

That doesn’t mean we must become hairshirt-wearing martyrs; developer convenience is important …but not as important as user needs. Start with user needs.

Design principles

Andrew Travers wrote about designing design principles at Co-op Digital. I’m somewhat obsessed with design principles—hence my collection—so I’m also obsessed with figuring out what makes for “good” design principles.

One of my favourite design principles (yes, I have favourites) is from the HTML Design Principles. It’s the priority of constituencies:

In case of conflict, consider users over authors over implementors over specifiers over theoretical purity.

The emphasis my own. It demonstrates how the design principle can be put to use (“in case of conflict”). Andrew also describes uses for the design principles they’re putting together:

What we’re building towards is a set of principles, few enough to be memorable, short enough to be repeatable, relevant enough to be usable. When we’re running a design crit, it’s these principles that we want to lean on. When a sole designer in an agile delivery team is talking about a design approach, it’s these principles that back her up.

Those sound like good use cases to me. Those are situations when design principles can help people reach agreement on priorities, without it having to be about ego or who shouts loudest.

I think it was from Cennydd that I heard about a really good test of a design principle: is it reversible? In other words, could you imagine the exact opposite of the design principle being perfectly valid in a different organisation or on a different project? If not, then the principle may be too weak to be effective. (Cennydd points out that he heard this from Jared who has written a lot about evaluating design principles.)

“Make it easy to use” would be an example of a weak design principle. It’s hard to imagine a situation where “make it hard to use” would be a reasonable guiding principle.

Frankly, there are plenty of “bad” examples in my collection of design principles. Many of them wouldn’t pass the reversibility test. Just recently though, I spotted some that would pass the test with flying colours. They weren’t even labelled as design principles—they’re the tips that Heydon includes at the end of his excellent 24 Ways article on inclusive design:

  • Involve code early
  • Respect conventions
  • Don’t be exact
  • Enforce simplicity

I could easily imagine endeavours where the complete opposite of those tips would be valued. Personally, I think they’re really great design princples.

I should add them to the list.

Celebrating CSS

Cascading Style Sheets turned 20 years old this week. Happy birthtime, CeeSusS!

Bruce interviewed Håkon about the creation of CSS, and it makes for fascinating reading. If you want to dig even deeper, here’s Håkon’s 1994 thesis comparing competing approaches to style sheets.

CSS gets a tough rap. I remember talking to Douglas Crockford about CSS. I’ll paraphrase his stance as “Kill it with fire!” To be fair, he was mostly talking about the lack of a decent layout system in CSS—something that’s only really getting remedied now.

Most of the flak directed at CSS comes from smart programmers, decrying its lack of power. As a declarative language, it lacks even the most basic features of even the simplest procedural language. How are serious programmers supposed to write their serious programmes with such a primitive feature set?

But I think this mindset misses out a crucial facet of understanding CSS: it’s not about us. By us, I mean professional web developers. And when I say it’s not about us, I mean it’s not only about us.

The web is for everyone. That doesn’t just mean that it’s for everyone to use—the web is for everyone to create. That means that the core building blocks of the web need to be learnable by everyone, not just programmers.

I get nervous when I see web browsers gaining powerful features that can only be accessed via a JavaScript API. Geolocation is one example: it doesn’t have any declarative equivalent to its JavaScript implementation. Counter-examples would be video and audio: you can use the JavaScript API to get exactly the behaviour you want, if you’ve got that level of knowledge …or you can use the video and audio elements if you’re okay with letting web browsers handle the complexity of display and playback.

I think that CSS hits a nice sweet spot, balancing learnability and power. I love the fact that every bit of CSS ever written comes down to the same basic pattern:

selector {
    property: value;

That’s it!

How amazing is it that one simple pattern can scale to encompass a whole wide world of visual design variety?

Think about the revolution that CSS has gone through in recent years: OOCSS, SMACSS, BEM …these are fundamentally new ways of approaching front-end development, and yet none of these approaches required any changes to be made to the CSS specification. The power and flexibility was already available within its simple selector-property-value pattern.

Mind you, that modularity was compromised when we got things like named animations; a pattern that breaks out of the encapsulation model of CSS. Variables in CSS also break out of the modularity pattern.

Personally, I don’t think there’s any reason to have variables in the CSS language; it’s enough to have them in pre-processing tools. Variables add enormous value for developers, and no value at all for end users. As long as developers can use variables—and they can, with Sass and LESS—I don’t think we need to further complicate CSS.

Bert Bos wrote an exhaustive list of design principles for web standards. There’s some crossover with Tim Berners-Lee’s principles of design, with ideas such as modularity and robustness. Personally, I think that Bert and Håkon did a pretty damn good job of balancing principles like learnability, extensibility, longevity, interoperability and a host of other factors while still producing something powerful enough to scale for the whole web.

There’s one important phrase I want to highlight in the abstract of the 20 year old CSS proposal:

The proposed scheme provides a simple mapping between HTML elements and presentation hints.


Every line of CSS you write is a suggestion. You are not dictating how the HTML should be rendered; you are suggesting how the HTML should be rendered. I find that to be a very liberating and empowering idea.

My only regret is that—twenty years on from the birth of CSS—web browsers are killing the very idea of user stylesheets. Along with “view source”, this feature really drove home the idea that professional web developers are not the only ones who have a say in what gets rendered in web browsers …and that the web truly is for everyone.


Emil has been playing around with CSS variables (or “custom properties” as they should more correctly be known), which have started landing in some browsers. It’s well worth a read. He does a great job of explaining the potential of this new CSS feature.

For now though, most of us will be using preprocessors like Sass to do our variabling for us. Sass was the subject of Chris’s talk at An Event Apart in San Francisco last week—an excellent event as always.

At one point, Chris briefly mentioned that he’s quite happy for variables (or constants, really) to remain in Sass and not to be part of the CSS spec. Alas, I didn’t get a chance to chat with Chris about that some more, but I wonder if his thinking aligns with mine. Because I too believe that CSS variables should remain firmly in the realm of preprocessers rather than browsers.

Hear me out…

There are a lot of really powerful programmatic concepts that we could add to CSS, all of which would certainly make it a more powerful language. But I think that power would come at an expense.

Right now, CSS is a relatively-straightforward language:

CSS isn’t voodoo, it’s a simple and straightforward language where you declare an element has a style and it happens.

That’s a somewhat-simplistic summation, and there’s definitely some complexity to certain aspects of CSS—like specificity or margin collapsing—but on the whole, it has a straightforward declarative syntax:

selector {
    property: value;

That’s it. I think that this simplicity is quite beautiful and surprisingly powerful.

Over at my collection of design principles, I’ve got a section on Bert Bos’s essay What is a good standard? In theory, it’s about designing standards in general, but it matches very closely to CSS in particular. Some of the watchwords are maintainability, modularity, extensibility, simplicity, and learnability. A lot of those principles are clearly connected. I think CSS does a pretty good job of balancing all of those principles, while still providing authors with quite a bit of power.

Going back to that fundamental pattern of CSS, you’ll notice that is completely modular:

selector {
    property: value;

None of those pieces (selector, property, value) reference anything elsewhere in the style sheet. But as soon as you introduce variables, that modularity is snapped apart. Now you’ve got a value that refers to something defined elsewhere in the style sheet (or even in a completely different style sheet).

But variables aren’t the first addition to CSS that sacrifices modularity. CSS animations already do that. If you want to invoke a keyframe animation, you have to define it. The declaration and the invocation happen in separate blocks:

selector {
    animation-name: myanimation;
@keyframes myanimation {
    from {
        property: value;
    to {
        property: value;

I’m not sure that there’s any better way to provide powerful animations in CSS, but this feature does sacrifice modularity …and I believe that has a knock-on effect for learnability and readability.

So CSS variables (or custom properties) aren’t the first crack in the wall of the design principles behind CSS. To mix my metaphors, the slippery slope began with @keyframes (and maybe @font-face too).

But there’s no denying that having variables/constants in CSS provide a lot of power. There’s plenty of programming ideas (like loops and functions) that would provide lots of power to CSS. I still don’t think it’s a good idea to mix up the declarative and the programmatic. That way lies XSLT—a strange hybrid beast that’s sort of a markup language and sort of a programming language.

I feel very strongly that HTML and CSS should remain learnable languages. I don’t just mean for professionals. I believe it’s really important that anybody should be able to write and style a web page.

Now does that mean that CSS must therefore remain hobbled? No, I don’t think so. Thanks to preprocessors like Sass, we can have our cake and eat it too. As professionals, we can use tools like Sass to wield the power of variables, functions (mixins) and other powerful concepts from the programming world.

Preprocessors cut the Gordian knot that’s formed from the tension in CSS between providing powerful features and remaining relatively easy to learn. That’s why I’m quite happy for variables, mixins, nesting and the like to remain firmly in the realm of Sass.

Incidentally, at An Event Apart, Chris was making the case that Sass’s power comes from the fact that it’s an abstraction. I don’t think that’s necessarily true—I think the fact that it provides a layer of abstraction might be a red herring.

Chris made the case for abstractions being inherently A Good Thing. Certainly if you go far enough down the stack (to Assembly Language), that’s true. But not all abstractions are good abstractions, and I’m not just talking about Spolky’s law of leaky abstractions.

Let’s take two different abstractions that share a common origin story:

  • Sass is an abstraction layer for CSS.
  • Haml is an abstraction layer for HTML.

If abstractions were inherently A Good Thing, then they would both provide value to some extent. But whereas Sass is a well-designed tool that allows CSS-savvy authors to write their CSS more easily, Haml is a steaming pile of poo.

Here’s the crucial difference: Sass doesn’t force you to write all your CSS in a completely new way. In fact, every .css file is automatically a valid .scss file. You are then free to use—or ignore—the features of Sass at your own pace.

Haml, on the other hand, forces you to use a completely new whitespace-significant syntax that maps on to HTML. There are no half-measures. It is an abstraction that is not only opinionated, it refuses to be reasoned with.

So I don’t think that Sass is good because it’s an abstraction; I think that Sass is good because it’s a well-designed abstraction. Crucially, it’s also easy to learn …just like CSS.

Whitney Hess: Design Principles — The Philosophy of UX

The second speaker at this mornings An Event Apart in Boston is Whitney Hess. Here goes with the liveblogging…

Whitney’s talk is about design principles. As a consultant, she spends a lot of time talking about UX and inevitably, the talk turns to deliverables and process but really we should be establishing a philosophy about how to treat people, in the same way that visual design is about establishing a philosophy about how make an impact. Visual design has principles to achieve that: contrast, emphasis, balance, proportion, rhythm, movement, texture, harmony and unity.

Why have these principles? It’s about establishing a basis for your design decisions, leading to consistency. It’s about having a shared vision and they allow for an objective evaluation of the outcome.

But good design doesn’t necessarily equate to a good experience. The Apple G4 Cube was beautifully designed but it was limited in where and how it could be used.

Good design can equal good experience. That’s why Whitney does what she does. But she needs our help. She’s going to propose a set of design principles that she feels are universally applicable.

  1. Stay out of people’s way. The Tumblr homepage does this. You can find out more about Tumblr further down the page, but it doesn’t assume that’s what you want to have thrust in your face. Instead the primary content is all about getting started with Tumblr straight away.
  2. Create a hierarchy that matches people’s needs. This is about prioritisation. uses different font sizes to match the hierarchy of importance on its “ways to save” page. Give the most crucial elements the greatest prominence. Use hierarchy to help people process information.
  3. Limit distractions. Don’t put pregnancy test kits next to condoms. On the web, Wanderfly does this right: one single path, completely self-contained. Multi-tasking is a myth. Let people focus on one task. Design for consecutive tasks, not concurrent.
  4. Provide strong information scent. Quora does a great job at this with its suggested search options. It’s actively helping you choose the right one. People don’t like to guess haphazardly, they like to follow their nose.
  5. Provide signposts and cues. Labelling is important. The Neiman Marcus e-commerce site does this right. It’s always clear where you are: the navigation is highlighted. You’d think that in 2011 this would be standard but you’d be surprised. Never let people get lost, especially on the web where there’s a limitless number of paths. Show people where they came from and where they’re going.
  6. Provide context. A sign that says “Back in 30 minutes” isn’t helpful if you’re in a hurry—you don’t know when the sign was put up. On the web, AirBnB provides everything you need to know on a listing page, all in one place. It’s self-contained and everything is communicated up-front.
  7. Use constraints appropriately. Preventing error is a lot better than recovering from it. If you know there are restrictions ahead of time, stop people from going down that route in the first place.
  8. Make actions reversible. (illustrated with a misspelled Glee tattoo) Remember The Milk provides an “undo?” link with almost every action. There’s no such thing as perfect design; people will make errors, so you should have a contingency plan. Undo is probably the most powerful control you can provide to people.
  9. Provide feedback. How do you know when you’re asthma inhaler is empty? You don’t. You won’t find out until the worst moment. On the web, loading indicators provide useful feedback. Tell people that a task is underway. Design is a conversation, not a monologue.
  10. Make a good first impression. Vimeo has one of the best first-time user experiences: “Welcome. You’re new, aren’t you?” Establish the rules, set expectations about the relationship you’re about to initiate on your site.

The basis for all of these principles are Aristotle’s modes of persuasion: logos, ethos and pathos—the rhetorical triangle.

Are universal principles enough? Probably not. Every company is different. Some companies publicly share their principles. Take Google’s “Ten Principles That Contribute to a Googley User Experience” as an example, or Facebook’s design principle …or Windows design principles for a good laugh. Look beyond the tech world too, like Charles and Ray Eames or Burning Man’s design principles.

So what are your company’s principles? Without principles, we don’t know what we’re trying to achieve. Here are some guiding ideas:

  1. Research available principles from elsewhere.
  2. Gather, list and print out the business goals and user needs.
  3. Brainstorm with key collaborators.
  4. Narrow down to no more than 10, preferably 7.
  5. Make sure they don’t overlap.
  6. Make them peppy.

Use the design principles at kickoff meetings, when your prioritising features, brainstorming sessions, design critiques, stakeholder presentations, resolving conflict, postmortems and web metric analysis: evaluating the success of the feature or product.

Remember, user experience is the establishment of a philosophy of how to treat people. Help people make their lives better.

Principles Apart

I was nervous as hell before my talk at An Event Apart Seattle. I don’t normally get quite so nervous but it was a new talk and also …it’s An Event Apart! They set a very, very high bar.

Once I got on stage though, I just started geeking out. I was talking about design principles, a subject I find fascinating. I’m hoping that some of my enthusiasm for the subject helped make for a compelling presentation.

It was a whirlwind tour, starting with a long-zoom look at design principles in history before moving on to the web, where I took an up-close-and-personal look at CSS and quite a bit of HTML, before pulling back again to talk about our planet, our solar system and our galaxy. Yes, there was a space elevator.

I mentioned a range of people, organisations and projects that have documented their design principles, but rather than fill up the slides with lots of URLs, I gave just one URL at the start (and end) of the talk:

That’s where I gathering today examples of documented design principles. By “documented” I mean “published on the web.” There are some really interesting principles from disciplines like urban design but as long as they are locked up in books that aren’t addressable on the network, I can’t link to them.

This is a fairly small-scale project so I figured a wiki might be overkill but if you know of any good documented design principles that should be added to the list, let me know

Jeremy Keith, Design Principles, Day II, #aea Jeremy Keith, Design Principles, Day II, #aea