Title: CSS Containment Module Level 3
Level: 3
Shortname: css-contain
Status: ED
Prepare for TR: no
Work Status: Revising
Group: csswg
ED: https://drafts.csswg.org/css-contain-3/
TR: https://www.w3.org/TR/css-contain-3/
Previous Version: https://www.w3.org/TR/2021/WD-css-contain-3-20211221/
Editor: Tab Atkins, Google, http://xanthir.com/contact/, w3cid 42199
Editor: Florian Rivoal, On behalf of Bloomberg, https://florian.rivoal.net/, w3cid 43241
Editor: Miriam E. Suzanne, Invited Expert, https://www.miriamsuzanne.com/who/, w3cid 117151
Abstract:
	This specification is a placeholder.
	It used to refine and extend features defined in CSS Containment Level 2,
	but extensions of containment been moved back to the Level 2 specification,
	while the main new feature it used to introduce has been moved to [[CSS-CONDITIONAL-5]].

	Having moved these features to other specifications,
	this document is now empty.
	It may be revived at a later point,
	when Level 2 stabilizes.
Privacy Considerations {#privacy} ================================= Not applicable. Security Considerations {#security} =================================== Not applicable.

Appendix A. Changes

This appendix is informative.

Changes since the 18 August 2022 Working Draft

Significant changes since the 18 August 2022 Working Draft include:
* Move the definition of inline-size containement from this Level 3 specification to Level 2. (Issue 10433) * Move Container Queries to [[CSS-CONDITIONAL-5]] (Issue 10433)
Prior to the move, the following significant changes had been made, and are reflected in [[CSS-CONDITIONAL-5]]: * List all values of 'contain' in order to clarify serialization order (Issue 8600) * Add the {{CSSContainerRule/containerName}} and {{CSSContainerRule/containerQuery}} attributes. (Issue 7033) * Correct typo in 'container-type' syntax, to clarify that ''container-type/normal'' cannot be combined with other values. (Issue 7669) * Allow ''var()'' references in [=container size queries=]. (Issue 8088) * Allow comma-separated <>s to match different containers. (Issue 7551)

Changes since the 21 December 2021 First Public Working Draft

Significant changes since the 21 December 2021 First Public Working Draft include: * Allow the computed value of 'container-name' to include duplicate identifiers. (Issue 7181) * Make the <<'container-name'>> in the 'container' shorthand required. (Issue 7142) * Clarify handling of [=shorthand properties=] in [=container style queries=]. (Issue 7095) * [=Cascade-dependent keywords=] are not allowed as values in a [=style feature=], and cause the [=container style query=] to be false. (Issue 7080) * Change the initial value of 'container-type' to be ''container-type/normal'', which establishes elements as containers for [=style features=]. (Issue 6393, Issue 7066, Issue 7402) * Remove the block-size value from 'container-type', since single-axis block-size containment is not currently possible. (Issue 1031) * Remove the <> option from the 'container-name' syntax. Container names must be <>s. (Issue 6405) * Reverse the order of <<'container-name'>> and <<'container-type'>> in the 'container' shorthand property, with both being optional. (Issue 6393) * Allow <> syntax in <>s, for the sake of forward compatibility. (Issue 6396) * Remove the size function syntax from <> queries. (Issue 6870) * Update the [=query container=] selection process to account for necessary container-types, and removed the explicit type-selection syntax. (Issue 6644) * Remove state query features, which have been deferred. (Issue 6402) * Clarify container selection around pseudo-elements and the shadow-DOM. (Issue 5984 and Issue 6711)

Changes from CSS Containment Level 2

* Introduces [=inline-size containment=]. * Defines the terms, properties, units, and at-rule needed for [=Container Queries=]