Can We Create a “Resize Hack” With Container Queries?

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Jhey Tompkins on (Updated on )

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If you follow new developments in CSS, you’ve likely heard of the impending arrival of container queries. We’re going to look at the basics here, but if you’d like another look, check out Una’s “Next Gen CSS: @container” article. After we have a poke at the basics ourselves, we’re going to build something super fun with them: a fresh take on the classic CSS meme featuring Peter Griffin fussing with window blinds. ;)

So, what is a container query? It’s… exactly that. Much like we have media queries for querying things such as the viewport size, a container query allows us to query the size of a container. Based on that, we can then apply different styles to the children of said container.

What does it look like? It’s something like this:

.container {
  container-name: my-container;
  container-type: inline-size;
  /* or */
  container: my-container inline-size;
}

@container my-container (min-width: 768px) {
  .child { background: hotpink; }
}

The my-container keyword targets the container for the container query by container-name. inline-size allows users to be more specific about containment. This currently means we can only query the container’s width. With size, we are able to query the container’s height.

You can use container queries (without a polyfill) as of Chrome version 105 and Safari 16. I would definitely recommend having a quick read through the drafts over on csswg.org.

The easiest way to start playing would be to whip up a couple of quick demos that sport a resizable container element.

Try changing the container values and see how the demos respond. These demos use container-type: size which doesn’t restrict the axis. When both the height and width of the containers meet certain thresholds, the shirt sizing adjusts in the first demo. The second demo shows how the axes can work individually instead, where the beard changes color, but only when adjusting the horizontal axis.

@container (min-width: 400px) and (min-height: 400px) {
  .t-shirt__container {
    --size: "L";
    --scale: 2;
  }
}

That’s what you need to know about container queries for now. It’s really just a few new lines of CSS.

The only thing is most demos for container queries I’ve seen so far use a pretty standard “card” example to demonstrate the concept. Don’t get me wrong, because cards are a great use case for container queries. A card component is practically the poster child of container queries. Consider a generic card design and how it could get affected when used in different layouts. This is a common problem. Many of us have worked on projects where we wind up making various card variations, all catering to the different layouts that use them.

But cards don‘t inspire much to start playing with container queries. I want to see them pushed to greater limits to do interesting things. I‘ve played with them a little in that t-shirt sizing demo. And I was going to wait until there was better browser support until I started digging in further (I’m a Brave user currently). But then Bramus shared there was a container query polyfill!

And this got me thinking about ways to “hack” container queries.

⚠️ Spoiler alert: My hack didn’t work. It did momentarily, or at least I thought it did. But, this was actually a blessing because it prompted more conversation around container queries. And now there is a new container queries polyfill.

What was my idea? I wanted to create something sort of like the “Checkbox Hack” but for container queries.

<div class="container">
  <div class="container__resizer"></div>
  <div class="container__fixed-content"></div>
</div>

The idea is that you could have a container with a resizable element inside it, and then another element that gets fixed positioning outside of the container. Resizing containers could trigger container queries and restyle the fixed elements.

.container {
  container: layout size;
}

.container__resize {
  resize: vertical;
  overflow: hidden;
  width: 200px;
  min-height: 100px;
  max-height: 500px;
}

.container__fixed-content {
  position: fixed;
  left: 200%;
  top: 0;
  background: red;
}

@container(min-height: 300px) {
  .container__fixed-content {
    background: blue;
  }
}

This did work with those earlier versions of the cqfill polyfill.

Can we debunk a classic CSS meme with container queries?

Seeing this work excited me a bunch. Finally, an opportunity to create a version of the Peter Griffin CSS meme with CSS and debunk it!

You’ve probably seen the meme. It’s a knock on the Cascade and how difficult it is to manage it. I created the demo using [email protected]… with my own little touches, of course. 😅

Moving the cord handle, resized an element which in turn affected the container size. Different container breakpoints would update a CSS variable, --open, from 0 to 1, where 1 is equal to an “open” and 0 is equal to a “closed” state.

@container (min-height: 54px) {
  .blinds__blinds {
    --open: 0.1;
  }
}
@media --css-container and (min-height: 54px) {
  .blinds__blinds {
    --open: 0.1;
  }
}
@container (min-height: 58px) {
  .blinds__blinds {
    --open: 0.2;
  }
}
@media --css-container and (min-height: 58px) {
  .blinds__blinds {
    --open: 0.2;
  }
}
@container (min-height: 62px) {
  .blinds__blinds {
    --open: 0.3;
  }
}
@media --css-container and (min-height: 62px) {
  .blinds__blinds {
    --open: 0.3;
  }
}

But…. as I mentioned, this hack isn’t possible.

What’s great here is that it prompted conversation around how container queries work. It also highlighted a bug with the container query polyfill which was fixed. I would love to see this “hack” work though.

Miriam Suzanne has been creating some fantastic content around container queries. The capabilities have been changing a bunch. That’s the risk of living on the bleeding edge. One of her latest articles sums up the current status.

Although my original demo/hack didn’t work, we can still kinda use a “resize” hack to create those blinds. Again, we can query height if we use container-type: size.

Consider this demo:

The arrow rotates as the container is resized. The trick here is to use a container query to update a scoped CSS custom property.

.container {
  container-type: size;
}

.arrow {
  transform: rotate(var(--rotate, 0deg));
}

@container(min-height: 200px) {
  .arrow {
    --rotate: 90deg;
  }
}

We‘ve kinda got a container query trick here then. The drawback with not being able to use the first hack concept is that we can’t go completely 3D. Overflow hidden will stop that. We also need the cord to go beneath the window which means the windowsill would get in the way.

But, we can almost get there.

This demo uses container query steps. At each step, a scoped custom property gets updated. This reveals Peter and opens the blinds.

The trick here is to scale up the container to make the resize handle bigger. Then I scale down the content to fit back where it’s meant to.

This fun demo “debunking the meme” isn’t 100% there yet, but, we’re getting close. Container queries are an exciting prospect. And it’ll be interesting to see how they change as browser support evolves. It’ll also be exciting to see how people push the limits with them or use them in different ways.

Who knows? The “Resize Hack” might fit in nicely alongside the infamous “Checkbox Hack” one day.

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Comments

  1. Brandon McConnell
    Permalink to comment#

    Great article, Jhey. I feel as though that hack should work. I’ll have to play with it to to better understand container queries too.

    Reply
  2. Jake Clarke
    Permalink to comment#

    I have just begun learning container queries. This helped me a lot. Thanks!

    Reply

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