Tuesday May 11, 2021 By David Quintanilla
A Primer On CSS Container Queries — Smashing Magazine

A prototype of the long-awaited CSS container queries has landed in Chrome Canary and is on the market for experimentation. Let’s take a look at what drawback is being solved, learn the way container queries work, and see how they evaluate with and complement current CSS options for format.

At current, container queries can be utilized in Chrome Canary by visiting chrome://flags and looking for and enabling them. A restart might be required.

View of the search results within Chrome Canary’s chrome://flags settings screen showing the “Enable CSS Container Queries” item with a status of “Enabled”
View of the search outcomes inside Chrome Canary’s chrome://flags settings display screen exhibiting the “Allow CSS Container Queries” merchandise with a standing of “Enabled”. (Large preview)

Observe: Please take into account that the spec is in progress, and will change at any time. You possibly can review the draft document which is able to replace because the spec is fashioned.

What Downside Are CSS Container Queries Fixing?

Almost 11 years in the past, Ethan Marcotte launched us to the concept of responsive design. Central to that concept was the provision of CSS media queries which allowed setting varied guidelines relying on the scale of the viewport. The iPhone had been launched three years prior, and we have been all making an attempt to determine tips on how to work inside this new world of contending with each cellular display screen sizes and desktop display screen sizes (which have been a lot smaller on common than right this moment).

Earlier than and even after responsive design was launched, many corporations handled the issue of fixing format primarily based on display screen measurement by delivering fully totally different websites, usually beneath the subdomain of m. Responsive design and media queries opened up many extra format options, and a few years of making finest practices round responding to viewport sizes. Moreover, frameworks like Bootstrap rose in recognition largely on account of offering builders responsive grid methods.

In newer years, design methods and part libraries have gained recognition. There’s additionally a want to construct as soon as, deploy wherever. That means a part developed in isolation is meant to work in any variety of contexts to make constructing advanced interfaces extra environment friendly and constant.

Sooner or later, these elements come collectively to make an internet web page or utility interface. Presently, with solely media queries, there may be usually an additional layer concerned to orchestrate mutations of elements throughout viewport adjustments. As talked about beforehand, a typical resolution is to make use of responsive breakpoint utility courses to impose a grid system, similar to frameworks like Bootstrap present. However these utility courses are a patch resolution for the restrictions of media queries, and sometimes lead to difficulties for nested grid layouts. In these conditions, you’ll have so as to add many breakpoint utility courses and nonetheless not arrive on the most supreme presentation.

Or, builders could also be utilizing sure CSS grid and flex behaviors to approximate container responsiveness. However flex and CSS grid solutions are restricted to solely loosely defining format changes from horizontal to vertical preparations, and don’t handle the necessity to modify different properties.

Container queries transfer us past contemplating solely the viewport, and permit any part or aspect to answer an outlined container’s width. So whereas you should still use a responsive grid for total web page format, a part inside that grid can outline its personal adjustments in habits by querying its container. Then, it will possibly modify its kinds relying on whether or not it’s displayed in a slim or large container.

See the Pen [Container Queries – Minimal Flexbox Grid Layout Example](https://codepen.io/smashingmag/pen/MWpaGpQ) by Stephanie Eckles.

See the Pen Container Queries – Minimal Flexbox Grid Layout Example by Stephanie Eckles.

Container queries move us beyond considering only the viewport, and allow any component or element to respond to a defined container’s width.

With container queries, you’ll be capable of outline a part’s full vary of kinds in a really exact and predictable method. Maybe you need to enhance or lower padding, change font sizes, add or take away background pictures, or fully change the show property and orientation of kid parts.

We’ll take a look at extra examples quickly, however first let’s discover ways to create a container question!

Getting Began With CSS Container Queries

The very first thing to learn about CSS container queries is that “containers” are the weather being queried, however guidelines inside container queries have an effect on solely the container descendants. In different phrases — you might outline most important as a container, or maybe article, and even listing gadgets. Then, container queries will permit defining guidelines for a way parts inside these change throughout container sizes.

For the present experimental prototype, there may be one property required to outline a component as a container, and that’s the current comprise property. That is vulnerable to altering, each by way of what values are used, in addition to the potential for a new property being launched as an alternative to assist outline containment.

Already, the comprise property takes one or a number of values, and support is gaining for the preliminary mixture of format measurement. The format worth creates a block formatting context that may comprise all its margins in order that the contents don’t have an effect on contents in one other container. The measurement worth requires setting express peak and width values or receiving dimensions extrinsically as from flex or grid dad and mom, as with this worth the aspect will not confirm its dimensions from its youngsters.

The principle purpose of browsers implementing these explicit values first was to organize for the potential for container queries. These containment values are set as much as remedy the problem of infinite looping that may very well be attributable to a baby aspect’s width altering its dad or mum width which adjustments the kid width once more.

The container query proposal is authored by Miriam Suzanne and defines a brand new worth of inline-size. Whereas measurement is for containment in each instructions (width and peak), the inline-size worth is for containment primarily based on width.

Miriam suggests that the majority usually CSS authors try to comprise parts primarily based on width. In the meantime, peak is allowed to be intrinsic — in different phrases, to develop or shrink primarily based on the aspect’s contents. Subsequently, inline-size is taken into account to be single axis containment. And it’s the worth that’s obtainable in Chrome Canary and permits us to start out experimenting with container queries.

Let’s create a category to have the ability to use for outlining parts as containers:

.container {
  comprise: format inline-size fashion;

We wanted to incorporate the values of format and inline-size for container queries to efficiently work. Moreover, Miriam suggested including fashion as nicely to keep away from a possible infinite loop from setting properties similar to counters which have potential to set off adjustments exterior of the container and have an effect on its measurement thus inflicting a resizing loop.

Now, earlier than we truly write a question, there are a couple of extra issues to know.

When you attach a container query, you are not modifying the container itself, but rather the elements within that container.

The usage of inline-size creates a containment context for parts inside that container. A queried aspect will use its nearest ancestor with containment utilized. That is vital, as a result of it’s allowed to nest containers. So in case you are unaware of what the container is or create a nested container, outcomes for descendants could change.

So, what does a container question truly seem like? The syntax might be acquainted from media queries, as they start with @container after which settle for a definition similar to (min-width: 300px).

Let’s assume we’ve positioned our container class on the <most important> aspect, and that it incorporates a collection of <articles>.

<most important class="container">
</most important>

Now we are able to arrange a container question to change the articles and any of their descendants which might be primarily based on the width of most important because it’s the containing aspect. To date in my experimentation, I’ve discovered it helpful to consider these much like the idea of “mobile-first”, besides on this case, it’s “narrowest container first”. That means, I’ll outline the kinds for my smallest anticipated container first, then use container queries to change kinds because the container grows.

article {
  padding: 1rem;
  font-size: 1rem;

@container (min-width: 60ch) {
  article {
    padding: 2rem;
    font-size: 1.25rem;

Observe that utilizing a font-relative unit like ch or em is meant to make use of the font-size of the container, however on the time of writing that’s not but full. So, for now, this might be utilizing the basis font measurement. There is a matter towards the spec for exploring different features that may become queryable.

The principles we added might not be advanced, however they’re sensible. In methods I’ve labored on, changes like what we’ve accomplished with padding are dealt with by making a collection of utility courses which are tied to viewport media queries. Now we are able to make them extra proportionate to parts primarily based on their contained measurement.

If we modify our most important container and outline a flex grid in order that the articles reply as flex youngsters, we’re going to hit what you may understand as a pitfall.

most important {
  show: flex;
  flex-wrap: wrap;

article {
  flex: 1 1 30ch;

What you may count on is that when the article’s width is lower than the 60ch we used for our container question is that it could tackle the decreased padding and font measurement. Nonetheless, because the articles are direct youngsters of most important and most important is the one containment context, the articles is not going to change till the width of most important is narrower than the container question. We might encounter the same difficulty if we’d used CSS grid to put out the articles.

To resolve this, every article must have a containing aspect added with a view to appropriately question for the width of the flex merchandise. It’s because the most important aspect is not consultant of the aspect’s width. On this case, the quickest decision is so as to add div parts with our container class round every article.

<most important class="container">
  <div class="container article"><article>...</article></div>
  <div class="container article"><article>...</article></div>
  <div class="container article"><article>...</article></div>
</most important>

We’ll additionally want to change our flex definition from the article to the brand new div, which we’ve additionally added the category of article for ease of writing our rule:

.article {
  flex: 1 1 30ch;

The result’s that when the most important container causes the flex gadgets to wrap, the final article spans the total width and may have the massive container kinds. Here’s a CodePen of this instance of container queries for flexbox children (reminder to view in Chrome Canary with container queries enabled as famous originally!).

The articles arranged by flex behavior to have two articles on the first row using the narrow container styles and the last article on the second row spanning full width with large container styles.
The articles organized by flex habits to have two articles on the primary row utilizing the slim container kinds and the final article on the second row spanning full width with giant container kinds. (Large preview)

We additionally saved most important as a container. This implies we can add kinds for the .article class, however they are going to be in response to the width of most important, not themselves. I’m anticipating this capacity to have guidelines inside container queries responding to a number of layers of containers trigger essentially the most confusion for preliminary implementation and later analysis and sharing of stylesheets.

Within the close to future, updates to browser’s DevTools will definitely help make DOM adjustments that alter all these relationships between parts and the containers they might question. Maybe an rising finest observe might be to solely question one stage up inside a given @container block, and to implement youngsters carrying their container with them to scale back the potential of destructive influence right here. The trade-off is the potential for extra DOM parts as we noticed with our article instance, and consequently dirtying semantics.

On this instance, we noticed what occurred with each nested containers and in addition the results of introducing flex or grid format right into a container. What’s at present unsettled within the spec is what occurs when a container question is outlined however there aren’t any precise container ancestors for these queried parts. It might be determined to contemplate containment to be false and drop the foundations, or they might fallback to the viewport. You possibly can monitor the open issue for fallback containment and even add your opinion to this dialogue!

Container Aspect Selector Guidelines

Earlier I discussed {that a} container can’t itself be styled inside a container question (except it’s a nested container and responding to its ancestor container’s question). Nonetheless, a container can be used as a part of the CSS selector for its youngsters.

Why is that this vital? It permits retaining entry to CSS pseudo-classes and selectors that could must originate on the container, similar to :nth-child.

Given our article instance, if we needed so as to add a border to each odd article, we are able to write the next:

@container (min-width: 60ch) {
  .container:nth-child(odd) > article {
    border: 1px stable gray;

If you should do that, you might need to use much less generic container class names to have the ability to determine in a extra readable method which containers are being queried for the rule.

Case Examine: Upgrading Smashing Journal’s Article Teasers

When you go to an creator’s profile right here on Smashing (such as mine) and resize your browser, you’ll discover the association of the article teaser parts change relying on the viewport width.

On the smallest viewports, the avatar and creator’s title are stacked above the headline, and the studying time and remark stats are slotted between the headline and article teaser content material. On barely bigger viewports, the avatar floats left of all of the content material, inflicting the headline to additionally sit nearer to the creator’s title. Lastly, on the most important viewports, the article is allowed to span practically the total web page width and the studying time and remark stats change their place to drift to the fitting of the article content material and under the headline.

Screenshot of the three layout adjustments described in the previous paragraph.
Screenshot of the three format changes described within the earlier paragraph. (Large preview)

By combining container queries with an improve to utilizing CSS grid template areas, we are able to replace this part to be aware of containers as an alternative of the viewport. We’ll begin with the slim view, which additionally implies that browsers that don’t help container queries will use that format.

Now for this demo, I’ve introduced the minimal needed current kinds from Smashing, and solely made one modification to the present DOM which was to maneuver the headline into the header part (and make it an h2).

Right here’s a decreased snippet of the article DOM construction to point out the weather we’re involved about re-arranging (unique class names retained):

<article class="article--post">
    <div class="article--post__image"></div>
    <span class="article--post__author-name"></span>
    <h2 class="article--post__title"></h2>
  <footer class="article--post__stats"></footer>
  <div class="article--post__content"></div>

We’ll assume these are direct youngsters of most important and outline most important as our container:

most important {
  comprise: format inline-size fashion;

Within the smallest container, we’ve got the three sections stacked: header, stats, and content material. Basically, they’re showing within the default block format in DOM order. However we’ll go forward and assign a grid template and every of the related parts as a result of the template is vital to our changes inside the container queries.

.article--post {
  show: grid;
    "content material";
  hole: 0.5rem;

.article--post header {
  grid-area: header;

.article--post__stats {
  grid-area: stats;

.article--post__content {
  grid-area: content material;

Grid is right for this job as a result of having the ability to outline named template areas makes it a lot simpler to use adjustments to the association. Plus, its precise format algorithm is extra supreme than flexbox for a way we need to handle to resize the areas, which can change into extra clear as we add within the container question updates.

Earlier than we proceed, we additionally must create a grid template for the header to have the ability to transfer across the avatar, creator’s title, and headline.

We’ll add onto the rule for .article--publish header:

.article--post header {
  show: grid;
    "avatar title"
    "headline headline";
  grid-auto-columns: auto 1fr;
  align-items: heart;
  column-gap: 1rem;
  row-gap: 0.5rem;

When you’re much less acquainted with grid-template-areas, what we’re doing right here is guaranteeing that the highest row has one column for the avatar and one for the title. Then, on the second row, we’re planning to have the headline span each of these columns, which we outline by utilizing the identical title twice.

Importantly, we additionally outline the grid-auto-columns to override the default habits the place every column takes up 1fr or an equal a part of the shared house. It’s because we would like the primary column to solely be as large because the avatar, and permit the title to occupy the remaining house.

Now we have to remember to explicitly place the associated parts into these areas:

.article--post__image {
  grid-area: avatar;

.article--post__author-name {
  grid-area: title;

.article--post__title {
  grid-area: headline;
  font-size: 1.5rem;

We’re additionally defining a font-size for the title, which we’ll enhance because the container width will increase.

Lastly, we are going to use flex to rearrange the stats listing horizontally, which would be the association till the most important container measurement:

.article--post__stats ul {
  show: flex;
  hole: 1rem;
  margin: 0;

Observe: Safari lately accomplished help of hole for flexbox, that means it’s supported for all fashionable browsers now! 🎉

The result of the grid template styles, showing the avatar and author name aligned, followed by the headline, then stats, then teaser content.
The results of the grid template kinds, exhibiting the avatar and creator title aligned, adopted by the headline, then stats, then teaser content material. (Large preview)

We will now transfer to our first of two container queries to create the midsize view. Let’s reap the benefits of having the ability to create font-relative queries, and base it on the container exceeding 60ch. In my view, making content material issues relative to line size is a sensible strategy to handle adjustments throughout container widths. Nonetheless, you may actually use pixels, rems, ems, and presumably extra choices sooner or later.

For this center measurement, we have to modify each the header and total article grid templates:

@container (min-width: 60ch) {
  .article--post header {
      "avatar title"
      "avatar headline";
    align-items: begin;

  .article--post {
    grid-template-areas: "header header" ". stats" ". content material";
    grid-auto-columns: 5rem 1fr;
    column-gap: 1rem;

  .article--post__title {
    font-size: 1.75rem;

At this width, we would like the avatar to look pulled into its personal column to the left of the remainder of the content material. To realize this, inside the header the grid template assigns it to the primary column of each rows, after which shifts the title to row one, column two, and the headline to row two, column two. The avatar additionally must be aligned to the highest now, so modify that with align-items: begin.

Subsequent, we up to date the article grid template in order that the header takes up each columns within the prime row. Following that, we use the . character to assign an unnamed grid space for the primary column of the second and third row, getting ready for the visible of the avatar showing in its personal column. Then, we modify the auto columns to make make the primary column equal to the avatar width to finish the impact.

The midsize container query layout with the avatar visually appearing to be in it’s own column to the left of the rest of the content.
The midsize container question format with the avatar visually showing to be in it’s personal column to the left of the remainder of the content material. (Large preview)

For the most important container measurement, we have to transfer the stats listing to look on the fitting of the article content material, however under the headline. We’ll once more use ch items for our “breakpoint”, this time selecting 100ch.

@container (min-width: 100ch) {
  .article--post {
    grid-template-areas: "header header header" ". content material stats";
    grid-auto-columns: 5rem fit-content(70ch) auto;

  .article--post__stats ul {
    flex-direction: column;

  .article--post__title {
    max-width: 80ch;
    font-size: 2rem;

  .article--post__content {
    padding-right: 2em;

To satisfy all of our necessities, we now must care for three columns, which makes the primary row a triple repeat of header. Then, the second row begins with an unnamed column shared with content material after which stats.

Taking a look at the true model of this web page, we see that the article doesn’t span 100% of the width of Smashing’s format. To retain this cover, inside the grid-auto-columns we’re utilizing the fit-content perform, which may be learn as: “develop up till intrinsic max-width of the content material, however no larger than the offered worth”. So, we’re saying the column can develop however not exceed 70ch. This doesn’t forestall it from shrinking, so the column stays aware of its obtainable house as nicely.

Following the content material column, we outline auto for the stats column width. This implies will probably be allowed to take the inline house it wants to suit its content material.

The largest article component arrangement moves the reading time and comment stats to the right of the main content, and the article content takes up the most horizontal space.
The most important article part association strikes the studying time and remark stats to the fitting of the primary content material, and the article content material takes up essentially the most horizontal house. (Large preview)

Now, you might be considering that we’ve type of simply accomplished media queries however in a barely totally different method. Which — if we pause a second — is type of nice! It ought to assist container queries really feel acquainted and make them simpler to regulate to and embody in your workflow. For our demo, it additionally at present feels that method as a result of our single article is at present responding to 1 dad or mum aspect which itself is simply responding to the altering viewport.

What we’re actually accomplished is ready the muse for this text to be dropped in on an article web page, or on the house web page the place the articles are organized in columns (for the sake of this demo, we’ll ignore the opposite adjustments that occur on the house web page). As we realized within the intro instance, if we would like parts to answer the width of CSS grid tracks or flex gadgets, we have to have them carry their container with them. So let’s add an express container aspect round every article as an alternative of counting on most important.

<div class="article--post-container">
    <article class="article--post"></article>

Then, we’ll assign .article--post-container as a container:

.article--post-container {
  comprise: format inline-size;

Now, if we create a flex-based grid format as we did within the intro instance, we’ll place one article by itself above that grid, and two inside the flex grid. This leads to the next changes because the containers change measurement:

The video helps show the adjustments that at the moment are in a position to occur fully independently of viewport-based media queries! That is what makes container queries thrilling, and why they’ve been wanted by CSS builders for thus lengthy.

Right here is the total CodePen of this demo together with the flex grid:

See the Pen [Container Queries Case Study: Smashing Magazine Article Excerpts](https://codepen.io/smashingmag/pen/KKWdRMq) by Stephanie Eckles.

See the Pen Container Queries Case Study: Smashing Magazine Article Excerpts by Stephanie Eckles.

Alternatives and Cautions for Utilizing Container Queries

You can begin getting ready to make use of container queries right this moment by together with them as a progressive enhancement. By defining kinds that work nicely with out container queries, you possibly can layer up enhancements that do use them. Then, unsupporting browsers will nonetheless obtain a workable — if lower than supreme — model.

As we glance in direction of the way forward for having the ability to use container queries wherever, listed below are some doable alternatives the place they are going to be useful, in addition to some cautions. All of them share one trait: they’re eventualities when it’s more likely to be thought-about fascinating that format and elegance adjustments might be unbiased from the viewport.

Responsive Typography

It’s possible you’ll be acquainted with the idea of responsive or fluid typography. Options for making typography replace throughout viewport and aspect widths have seen many developments, from JavaScript aiding, to CSS options utilizing clamp() and viewport items.

If the spec receives a container unit (which we’ll speak about shortly), we could possibly obtain intrinsic typography. However even with the present spec, we are able to outline responsive typography by altering the font-size worth throughout varied sizes of contained parts. In reality, we simply did this within the instance of the Smashing Journal articles.

Whereas that is thrilling from a design and format viewpoint, it comes with the identical warning as current fluid typography options. For accessibility, a consumer ought to be capable of zoom the format and enhance font-size to 200% of its unique measurement. When you create an answer that drastically shrinks font measurement in smaller containers — which often is the computed measurement upon zoom — a consumer could by no means be capable of obtain rising the bottom font-size by 200%. I’m certain we are going to see extra tips and options round this as all of us get extra acquainted with container queries!

Altering Show Values

With container queries, we’ll be capable of fully change show properties, similar to from grid to flex. Or change their associated properties, like replace grid templates. This makes method for easily repositioning baby parts primarily based on the present house allowed to the container.

That is the class you’ll discover most of the present demos fall into, because it appears to be one of many issues that makes the potential for container queries so thrilling. Whereas responsive grid methods are primarily based on media queries tied to viewport width, you might end up including layers of utility courses to get the outcome you’re actually after. However with container queries, you possibly can precisely specify not solely a grid system, however fully change it because the aspect or part grows and shrinks.

Attainable eventualities embody:

  • altering a e-newsletter subscription type from horizontal to stacked format;
  • creating alternating grid template sections;
  • altering picture side ratios and their place versus associated content material;
  • dynamic contact playing cards that reposition avatars and speak to particulars and may be dropped in a sidebar simply as simply as a page-width part

Right here it needs to be famous that simply as in our pre-container question world, for accessibility it’s suggested to make sure a logical order particularly for the sake of tabbing interactive parts like hyperlinks, buttons, and type parts.

Exhibiting, Hiding And Rearranging

For extra advanced elements, container queries can step in and handle variations. Contemplate a navigation menu that features a collection of hyperlinks, and when the container is decreased, a few of these hyperlinks ought to cover and a dropdown ought to seem.

Container queries can be utilized to look at sections of the navigation bar and alter these particular person components independently. Distinction this to making an attempt to deal with this with media queries, the place you may choose to design and develop towards breakpoints with the results of a compromised, much less supreme last resolution.

Develop As soon as, Deploy Anyplace

Okay, this is likely to be a bit aspirational. However for design methods, part libraries, and framework builders, container queries will significantly enhance the flexibility to ship self-defensive options. Parts’ capacity to handle themselves inside any given house will cut back issues launched when it comes time to really add them right into a format.

At first thought, this looks as if the dream, particularly in case you’ve been concerned with design system improvement as I’ve. Nonetheless, the professionals and cons could also be equal for some elements, and you might not at all times need the dynamic format or repositioning habits. I anticipate this might be one other space finest practices will type to maybe have elements opt-in to utilizing container question habits per occasion, similar to by way of a modifier class.

For instance, think about a card part that assumes that font-size ought to change. However, in a selected occasion, the precise character counts have been for much longer or a lot shorter and people guidelines have been suboptimal. An opt-in would probably be simpler than making an attempt to override each single container question that was connected.

What May Change within the Spec

Presently, even the syntax is topic to vary earlier than the spec is totally finalized. In reality, it’s been launched as an experiment in order that as a neighborhood we are able to present suggestions. Miriam Suzanne has created a GitHub project to track issues, and you might react to these and add feedback.

I already talked about two key points but to be resolved:

  • #6178: How does @container resolve when no ancestor containers have been outlined?
  • #5989: What container options may be queried?

Of excessive significance and influence is:

  • Ought to there be a brand new syntax for establishing queryable containers? (#6174)
    The preliminary difficulty from Miriam proposes two choices of both a brand new set of devoted comprise values or a completely new property maybe referred to as containment. If any of those adjustments come by way of within the prototype section, the values demonstrated at first of this text could not work. So as soon as once more, be aware that it’s nice to experiment, however remember that issues will proceed altering!

Additionally of curiosity is the potential for new container items, tracked in:

  • [“container width” and “container height” units (#5888)
    This could open up a native CSS solution for intrinsic typography among other things, something like: font-size: clamp(1.5rem, 1rem + 4cw, 3rem) (where cw is a placeholder for a currently undefined unit that might represent container width).

Additional Demos And Resources

Smashing Editorial
(vf, il)

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