Day 59: naming containers

posted on 15.12.2022

It’s time to get me up to speed with modern CSS. There’s so much new in CSS that I know too little about. To change that I’ve started #100DaysOfMoreOrLessModernCSS. Why more or less modern CSS? Because some topics will be about cutting-edge features, while other stuff has been around for quite a while already, but I just have little to no experience with it.

When you add a container query, it will look for the nearest ancestor container, by default. If you have multiple nested containers or if you just want to make sure that your query uses the right container, you can name containers and query them specifically.

Let's say, we have 2 size containers, .wrapper and <section>.

<div class="wrapper">
  <section>
    <h2>Latest news</h2>

    <div class="card">
      <h2>Hey, I'm a card!</h2>
    </div>
  </section>
</div>

/* That's our outer size container. */
.wrapper {
  container-type: inline-size;
}

/* That's our inner size container. */
section {
  width: 50%;
  container-type: inline-size;
}

/* Default styles for the card. */
.card {
  background-color: yellow;
  border: 5px solid;
}

/* Container query */
@container (min-width: 500px) {
  .card {
    background-color: hotpink;
  }
}

By default, the container query watches the width of the closest size container, <section>. You can grab and resize the <section> by clicking and dragging it in the bottom right corner. The background color of the .card changes as soon as the width of the parent section hits 500px.

By naming the container and using that name in the query, you can target a specific container.

/* That's our outer size container. */
.wrapper {
  container-type: inline-size;
  container-name: wrapper;
}

/* That's our inner size container. */
section {
  container-type: inline-size;
}

/* The query watches the width of the outer size container (.wrapper) */
@container wrapper (min-width: 500px) {
  .card {
    background-color: hotpink;
  }
}

You can grab and resize the .wrapper by clicking and dragging it in the bottom right corner. The background color of the .card changes as soon as the width of the .wrapper is lower than 500px.

See on CodePen

Further reading

• Use the Right Container Query Syntax
• CSS Containment Module Level 3
• Day 56: container queries
• Day 62: the container shorthand
• Day 65: using the em unit in container queries
• Day 69: width in container queries
• Day 73: size container features
• Day 78: container query units
• Day 90: scoped styles in container queries

Overview: 100 Days Of More Or Less Modern CSS