Container Queries: Components That Adapt

Media queries ask "how wide is the viewport?" Container queries ask "how wide is my box?" — which is what components actually need.

Setup

.card-wrapper {
  container-type: inline-size;
}

@container (min-width: 400px) {
  .card {
    display: grid;
    grid-template-columns: 96px 1fr;
  }
}

container-type: inline-size marks the element as a size container on the inline axis. The @container rule applies its styles based on the nearest ancestor container — the same .card can be horizontal in a wide sidebar slot and vertical in a narrow one, with no JavaScript and no viewport assumptions.

Why this changes architecture

With media queries, a component's looks depend on where the page is — so reusing a card in two layouts means duplicating breakpoints. With containers, the component owns its responsive behavior; drop it anywhere and it adapts. This is the foundation of design systems built from independent parts.

Fluid type with clamp()

Between fixed breakpoints, clamp() interpolates smoothly:

h1 {
  font-size: clamp(1.75rem, 1rem + 3vw, 3.5rem);
}
/* min, preferred (grows with viewport), max */

Pair clamp() with container-query layout and components stay readable from 320px to ultrawide without a single extra breakpoint.