Tags: queries

Time for even more CSS goodness at An Event Apart Seattle (Special Edition). Eric’s talk is called Fit For Purpose: Making Sense of the New CSS. Here are my notes…

Eric isn’t going to dive quite as deeply as Rachel, but he is going to share some patterns he has used.

Feature queries

First up: feature queries! Or @supports, if you prefer. You can ask a browser “do you support this feature?” If you haven’t used feature queries, you might be wondering why you have to say the property and the value. Well, think about it. If you asked a browser “do you support display?”, it’s not very useful. So you have to say “do you support display: grid?”

Here’s a nice pattern from Lea Verou for detecting support for custom properties:

@supports (--css: variables)

Here’s a gotcha:

@supports (clip-path: polygon())

That won’t work because polygon() is invalid. This will work:

@supports (clip-path: polygon(0 0))

So to use feature queries, you need to understand valid values for properties.

You can chain feature queries together, or just pick the least-supported thing you’re testing for and test just for that.

Here’s a pattern Eric used when he only wanted to make text sideways, but only if grid is supported:

@supports (display: grid) {
    ...
    @supports (writing-mode: sideways-lr) {
        ...
    }
}

That’s functionally equivalent to:

@supports (display: grid) {
    ...
}
@supports (display:grid) and (writing-mode: sideways-lr) {
    ...
}

Choose whichever pattern makes sense to you. More to the point, choose the pattern that makes sense to your future self when you revisit your code.

Feature queries need to work together with media queries. Sometimes there are effects that you only want to apply on larger viewports. Do you put your feature queries inside your media queries? Or do you put your media queries inside your feature queries?

• MOSS: Media Outside Support Statements
• MISO: Media Inside Supports Object

Use MOSS when you have more media switches than support blocks. Use MISO when you only have a few breakpoints but lots of feature queries.

That’s one idea that Eric has. It’ll be interesting to see how this develops.

And remember, CSS is still CSS. Sometimes you don’t need a feature query at all. You could just use hanging-punctuation without testing for it. Browsers that don’t understand it will just ignore it. CSS has implicit feature queries built in. You don’t have to put your grid layout in a feature query, but you might want to put grid-specific margins and widths inside a feature query for display: grid.

Feature queries really help us get from now to the future.

Flexbox

Let’s move on to flexbox. Flexbox is great for things in a line.

On the An Event Apart site, the profile pictures have social media icons lined up at the bottom. Sometimes there are just a few. Sometimes there are a lot more. This is using flexbox. Why? Because it’s cool. Also, because it’s flexbox, you can create rules about how the icons should behave if one of the icons is taller than the others. (It’s gotten to the point that Eric has forgotten that vertically-centring things in CSS is supposed to be hard. The jokes aren’t funny any more.) Also, what if there’s no photo? Using flexbox, you can say “if there’s no photo, change the direction of the icons to be vertical.” Once again, it’s all about writing less CSS.

Also, note that the profile picture is being floated. That’s the right tool for the job. It feels almost transgressive to use float for exactly the purpose for which it was intended.

On the An Event Apart site, the header is currently using absolute positioning to pull the navigation from the bottom of the page source to the top of the viewport. But now you get overlap at some screen sizes. Flexbox would make it much more robust. (Eric uses the flexbox inspector in Firefox Nightly to demonstrate.)

With flexbox, what works horizontally works vertically. Flexbox allows you to align things, as long as you’re aligning in one direction. Flexbox makes things springy. Everything’s related and pushing against each other in a way that makes sense for this medium. It’s intuitive, even though it takes a bit of getting used to …because we’ve picked up some bad habits. To quote Yoda, “You must unlearn what you have learned.” A lot of the barrier is getting over what we’ve internalised. Eric envies the people starting out now. They get to start fresh. It’s like when people who never had to table layouts see code from that time period: it (quite rightly) doesn’t make any sense. That’s what it’s going to be like when people starting out today see the float-based layouts from Bootstrap and the like.

Grid

That’s going to happen with grid too. We must unlearn what we have learned from twenty years of floats and positioning. What makes it worth is:

1. Flexbox and grid are pretty easy to get used to, and
2. It’s amazing what you can do!

Eric quotes from an article called How We adopted CSS Grid at Scale:

…we agreed to use CSS Grid at the layout level and Flexbox at the component level (arranging child items of components). Although there’s some overlap and in some cases both could be used interchangeably, abiding by this rule helped us avoid any confusion in gray areas.

Don’t be afraid to set these kind of arbitrary limits that aren’t technological, but are necessary for the team to work well together.

Eric hacked his Wordpress admin interface to use grid instead of floats for an activity component (a list of dates and titles). He initially turned each list item into a separate grid. The overall list didn’t look right. What Eric really needed was a subgrid capability, so that the mini grids (the list items) would relate to one another within the larger grid (the list). But subgrid doesn’t exist yet.

In this case, there’s a way to fake it using display: contents. Eric made the list a grid and used display: contents on the list items. It’s as though you’re saying that the contents of the li are really the contents of the ul. That works in this particular case.

The feature queries for that looked like:

@supports (display: grid) {
    ...
    @supports (display: contents) {
        ...
    }
}

Eric is also using the grid “ASCII art” (named areas) technique on his personal site. This works independent of source order. For that reason, make sure your source order makes sense.

Using media queries, Eric defines entirely different layouts simply by using different ASCII art. He’s switching templates.

For a proposed redesign of the An Event Apart site, Eric used CSS grid as a prototyping tool. He took a PDF, sliced it up, exported JPGs, and then used grid to lay out those images in a flexible grid. Rapid prototyping! The Firefox grid inspector really helps here. In less than an hour, he had a working layout. He could test whether the layout was sensible and robust. Then he swapped out the sliced images for real content. That took maybe another hour (mostly because it was faster to re-type the text than try to copy and paste from a PDF). CSS makes it that damn easy now!

So even if you’re not going to put things like grid into production, they can still be enormously useful as design tools (and you’re getting to grips with this new stuff).

See also:

• Torre’s notes from this talk.

Every single browser maker has the same stance when it comes to features—they want to hear from developers at the coalface.

“Tell us what you want! We’re listening. We want to know which features to prioritise based on real-world feedback from developers like you.”

“How about container quer—”

“Not that.”

I don’t think it’s an exaggeration to say that literally every web developer I know would love to have container queries. If you’ve worked on any responsive project of any size, you’re bound to have bumped up against the problem of only being able to respond to viewport size, rather than the size of the containing element. Without container queries, our design systems can never be truly modular.

But there’s a divide growing between what our responsive designs need to do, and the tools CSS gives us to meet those needs. We’re making design decisions at smaller and smaller levels, but our code asks us to bind those decisions to a larger, often-irrelevant abstraction of a “page.”

But the message from browser makers has consistently been “it’s simply too hard.”

At the Frontend United conference in Athens a little while back, Jonathan gave a whole talk on the need for container queries. At the same event, Serg gave a talk on Houdini.

Now, as I understand it, Houdini is the CSS arm of the extensible web. Just as web components will allow us to create powerful new HTML without lobbying browser makers, Houdini will allow us to create powerful new CSS features without going cap-in-hand to standards bodies.

At this year’s CSS Day there were two Houdini talks. Tab gave a deep dive, and Philip talked specifically about Houdini as a breakthrough for polyfilling.

During the talks, you could send questions over Twitter that the speaker could be quizzed on afterwards. As Philip was talking, I began to tap out a question: “Could this be used to polyfill container queries?” My thumb was hovering over the tweet button at the very moment that Philip said in his talk, “This could be used to polyfill container queries.”

For that happen, browsers need to implement the layout API for Houdini. But I’m betting that browser makers will be far more receptive to calls to implement the layout API than calls for container queries directly.

Once we have that, there are two possible outcomes:

1. We try to polyfill container queries and find out that the browser makers were right—it’s simply too hard. This certainty is itself a useful outcome.
2. We successfully polyfill container queries, and then instead of asking browser makers to figure out implementation, we can hand it to them for standardisation.

But, as Eric Portis points out in his talk on container queries, Houdini is still a ways off (by the way, browser makers, that’s two different conference talks I’ve mentioned about container queries, just in case you were keeping track of how much developers want this).

Still, there are some CSS features that are Houdini-like in their extensibility. Custom properties feel like they could be wrangled to help with the container query problem. While it’s easy to think of custom properties as being like Sass variables, they’re much more powerful than that—the fact they can be a real-time bridge between JavaScript and CSS makes them scriptable. Alas, custom properties can’t be used in media queries but maybe some clever person can figure out a way to get the effect of container queries without a query-like syntax.

However it happens, I’d just love to see some movement on container queries. I’m not alone.

I know container queries would revolutionize my design practice, and better prepare responsive design for mobile, desktop, tablet—and whatever’s coming next.

I made a little tweak to The Session today. The navigation bar across the top is “sticky” now—it doesn’t scroll with the rest of the content.

I made sure that the stickiness only kicks in if the screen is both wide and tall enough to warrant it. Vertical media queries are your friend!

But it’s not enough to just put some position: fixed CSS inside a media query. There are some knock-on effects that I needed to mitigate.

I use the space bar to paginate through long pages. It drives me nuts when sites with sticky headers don’t accommodate this. I made use of Tim Murtaugh’s sticky pagination fixer. It makes sure that page-jumping with the keyboard (using the space bar or page down) still works. I remember when I linked to this script two years ago, thinking “I bet this will come in handy one day.” Past me was right!

The other “gotcha!” with having a sticky header is making sure that in-page anchors still work. Nicolas Gallagher covers the options for this in a post called Jump links and viewport positioning. Here’s the CSS I ended up using:

:target:before {
    content: '';
    display: block;
    height: 3em;
    margin: -3em 0 0;
}

I also needed to check any of my existing JavaScript to see if I was using scrollTo anywhere, and adjust the calculations to account for the newly-sticky header.

Anyway, just a few things to consider if you’re going to make a navigational element “sticky”:

1. Use min-height in your media query,
2. Take care of keyboard-initiated page scrolling,
3. Adjust the positioning of in-page links.