The CSS containment module defines containment and container queries.

Containment enables the isolation of page subtrees from the rest of the DOM. The browser can then improve performance by optimizing the rendering of these independent parts.

Container queries are similar to dimension media queries, except that the queries are based on the dimensions of a specific container element defined as a containment context, rather than on the dimensions of the viewport. Container queries enable querying a container's size, properties, property values, or even just its assigned container-name to conditionally apply CSS styles. When applying these conditional styles, you can use container query length units, which specify lengths relative to the dimensions of the query container. Additional properties are defined to enable establishing a specific element as a query container and giving it a specific name.

Reference

Properties

• contain
• content-visibility

Events

• contentvisibilityautostatechange

Interfaces

• ContentVisibilityAutoStateChangeEvent
  • skipped property
• CSSContainerRule
  • CSSContainerRule.containerName
  • CSSContainerRule.containerQuery

Guides

CSS container queries

A guide to using container queries with @container, including naming containment contexts.

Using CSS containment

Describes the basic aims of CSS containment and how to leverage contain and content-visibility for a better user experience.

Using container size and style queries

A guide to writing container size and style queries with @container, including style queries for custom properties, query syntax and names, and nesting container queries.

Related concepts

• Layout and the containing block

• Block formatting context

• CSS conditional rules module

  • @container at-rule
  • container property
  • container-name property
  • container-type property

• CSS media queries module

  • @media at-rule
  • CSS logical operators (not, or, and and)

• CSS transitions module

  • @starting-style at-rule
  • transition-behavior property

• CSS box sizing module

  • aspect-ratio property
  • contain-intrinsic-size shorthand property
  • contain-intrinsic-inline-size property
  • contain-intrinsic-block-size property
  • contain-intrinsic-width property
  • contain-intrinsic-height property

• CSS counter styles module

  • Using CSS counters guide

• CSS nesting module

  • CSS nesting at-rules guide

Specifications

See also

• Using feature queries
• Using CSS media queries
• Understanding aspect ratios
• @supports at-rule