Cascading Style Sheets (CSS) Working Group - IPR

Licensing Commitments

Participants in this group have made certain licensing commitments by joining the group. In addition to these Participants, non-participating W3C Member may have made licensing commitments.

W3C Members not participating in this group who wish to make the same licensing commitments for specifications developed by this group may do so through a Join form for licensing commitments from non-participating Members.

Other parties making a substantive contribution to the work of the group need to make a Royalty-Free patent commitment, as described in section 6.2.6 of the Process. Team contacts will provide instructions for recording the non-participant licensing commitment before the contribution can be accepted.

Participation

W3C Member Organizations

• 360
• Adobe
• Alibaba Group
• Amazon
• Apple Inc.
• Baidu, Inc.
• BFO
• Bloomberg
• British Broadcasting Corporation
• ByteDance
• Datadog
• Electronics and Telecommunications Research Institute (ETRI)
• eyeo GmbH
• Google LLC
• IBM Corporation
• Igalia
• Intel Corporation
• Kodansha, Publishers, Ltd.
• LG Electronics
• LSEG
• Microsoft Corporation
• Ministry of Digital Affairs, Taiwan
• MITRE Corporation
• Monotype
• MovieLabs
• Mozilla Foundation
• Navy Federal Credit Union
• Rakuten Group, Inc.
• Salesforce
• Samsung Electronics Co., Ltd.
• Shopify
• Skynet Technologies
• Taiwan Digital Publishing Forum
• Tencent
• TetraLogical Services Ltd
• The New York Times
• The Washington Post
• Thomson Reuters Corp.
• TPGi
• Wix.com Ltd.

Note: Log in to see links to organizations if you have member access

Invited Experts

• Brian Birtles
• Amy Carney
• Hidde de Vries
• Dael Jackson
• Brad Kemper
• Jirka Kosek
• Guillaume Lebas
• Vladimir Levantovsky
• Peter Linss
• Romain Menke
• Jonathan Neal
• François Remy
• Florian Rivoal
• Miriam Suzanne
• Lea Verou
• Sebastian Zartner

Team members

• Richard Ishida
• Chris Lilley
• Fuqiao Xue

See also the list of individuals participating in this group.

The Call for Participation for this group was announced on 2023-01-12; see the Patent Policy FAQ for information about continued participation before re-joining the group.

Specifications published by the Group

The following is the list of specifications produced by the Cascading Style Sheets (CSS) Working Group that have associated disclosures obligations, and possible licensing obligations under the W3C Patent Policy.

Documents under the W3C Patent Policy

Document	Patent Disclosure	Patent Exclusion
CSS Namespaces Module Level 3	disclose	exclude
Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification	disclose	exclude
Cascading Style Sheets, level 1	disclose	exclude
Selectors Level 3	disclose	exclude
CSS Cascading and Inheritance Level 3	disclose	exclude
CSS Multi-column Layout Module Level 1	disclose	exclude
CSS Values and Units Module Level 3	disclose	exclude
Media Queries Level 3	disclose	exclude
CSS Style Attributes	disclose	exclude
CSS Backgrounds and Borders Module Level 3	disclose	exclude
CSS3 module: Border	disclose	exclude
CSS Box Model Module Level 3	disclose	exclude
CSS Fonts Module Level 3	disclose	exclude
CSS3 module: line	disclose	exclude
CSS Lists and Counters Module Level 3	disclose	exclude
CSS Ruby Annotation Layout Module Level 1	disclose	exclude
CSS Basic User Interface Module Level 3 (CSS3 UI)	disclose	exclude
CSS Color Module Level 3	disclose	exclude
CSS Text Module Level 3	disclose	exclude
CSS Generated Content Module Level 3	disclose	exclude
CSS Paged Media Module Level 3	disclose	exclude
CSS Speech Module Level 1	disclose	exclude
CSS Syntax Module Level 3	disclose	exclude
SVG's XML Binding Language (sXBL)	disclose	exclude
CSS Generated Content for Paged Media Module	disclose	exclude
CSS Grid Positioning Module Level 3	disclose	exclude
CSSOM View Module	disclose	exclude
CSS 2D Transforms	disclose	exclude
CSS 3D Transforms Module Level 3	disclose	exclude
CSS Animations Level 1	disclose	exclude
CSS Flexible Box Layout Module Level 1	disclose	exclude
CSS Images Module Level 3	disclose	exclude
CSS Transitions	disclose	exclude
CSS Writing Modes Level 3	disclose	exclude
CSS Device Adaptation Module Level 1	disclose	exclude
CSS Conditional Rules Module Level 3	disclose	exclude
CSS Exclusions Module Level 1	disclose	exclude
CSS Grid Layout Module Level 1	disclose	exclude
CSS Regions Module Level 1	disclose	exclude
CSS Object Model (CSSOM)	disclose	exclude
Selectors Level 4	disclose	exclude
Compositing and Blending Level 1	disclose	exclude
CSS Counter Styles Level 3	disclose	exclude
CSS Masking Module Level 1	disclose	exclude
CSS Text Decoration Module Level 3	disclose	exclude
CSS Custom Properties for Cascading Variables Module Level 1	disclose	exclude
CSS Box Alignment Module Level 3	disclose	exclude
CSS Fragmentation Module Level 3	disclose	exclude
CSS Positioned Layout Module Level 3	disclose	exclude
CSS Box Sizing Module Level 3	disclose	exclude
CSS Transforms Module Level 1	disclose	exclude
CSS Images Module Level 4	disclose	exclude
CSS Overflow Module Level 3	disclose	exclude
Filter Effects Module Level 1	disclose	exclude
CSS Shapes Module Level 1	disclose	exclude
Web Animations	disclose	exclude
CSS Display Module Level 3	disclose	exclude
CSS Font Loading Module Level 3	disclose	exclude
CSS Line Grid Module Level 1	disclose	exclude
CSS Scoping Module Level 1	disclose	exclude
CSS Will Change Module Level 1	disclose	exclude
Geometry Interfaces Module Level 1	disclose	exclude
Media Queries Level 4	disclose	exclude
CSS Inline Layout Module Level 3	disclose	exclude
CSS Pseudo-Elements Module Level 4	disclose	exclude
CSS Scroll Snap Module Level 1	disclose	exclude
Motion Path Module Level 1	disclose	exclude
CSS Cascading and Inheritance Level 4	disclose	exclude
CSS Page Floats	disclose	exclude
CSS Round Display Level 1	disclose	exclude
CSS Text Module Level 4	disclose	exclude
CSS Basic User Interface Module Level 4	disclose	exclude
Cascading Style Sheets Level 2 Revision 2 (CSS 2.2) Specification	disclose	exclude
CSS Painting API Level 1	disclose	exclude
CSS Properties and Values API Level 1	disclose	exclude
CSS Typed OM Level 1	disclose	exclude
CSS Color Module Level 4	disclose	exclude
CSS Table Module Level 3	disclose	exclude
CSS Easing Functions Level 1	disclose	exclude
CSS Containment Module Level 1	disclose	exclude
CSS Rhythmic Sizing	disclose	exclude
CSS Fill and Stroke Module Level 3	disclose	exclude
CSS Logical Properties and Values Level 1	disclose	exclude
CSS Overflow Module Level 4	disclose	exclude
CSS Fonts Module Level 4	disclose	exclude
CSS Writing Modes Level 4	disclose	exclude
CSS Grid Layout Module Level 2	disclose	exclude
CSS Text Decoration Module Level 4	disclose	exclude
CSS Layout API Level 1	disclose	exclude
CSS Values and Units Module Level 4	disclose	exclude
CSS Scrollbars Styling Module Level 1	disclose	exclude
CSS Shadow Parts	disclose	exclude
CSS Fragmentation Module Level 4	disclose	exclude
CSS Spatial Navigation Level 1	disclose	exclude
CSS Color Adjustment Module Level 1	disclose	exclude
CSS Overscroll Behavior Module Level 1	disclose	exclude
CSS Animation Worklet API	disclose	exclude
CSS Containment Module Level 2	disclose	exclude
Resize Observer	disclose	exclude
CSS Scroll Anchoring Module Level 1	disclose	exclude
CSS Color Module Level 5	disclose	exclude
Media Queries Level 5	disclose	exclude
CSS Transforms Module Level 2	disclose	exclude
CSS Conditional Rules Module Level 4	disclose	exclude
CSS Box Model Module Level 4	disclose	exclude
CSS Box Sizing Module Level 4	disclose	exclude
CSS Custom Highlight API Module Level 1	disclose	exclude
CSS Cascading and Inheritance Level 5	disclose	exclude
CSS Fonts Module Level 5	disclose	exclude
CSS Nesting Module	disclose	exclude
CSS Containment Module Level 3	disclose	exclude
CSS Cascading and Inheritance Level 6	disclose	exclude
CSS Conditional Rules Module Level 5	disclose	exclude
CSS View Transitions Module Level 1	disclose	exclude
Scroll-driven Animations	disclose	exclude
Web Animations Level 2	disclose	exclude
CSS Animations Level 2	disclose	exclude
CSS Anchor Positioning	disclose	exclude
CSS Transitions Level 2	disclose	exclude
CSS Viewport Module Level 1	disclose	exclude
CSS View Transitions Module Level 2	disclose	exclude
CSS Scroll Snap Module Level 2	disclose	exclude
CSS Easing Functions Level 2	disclose	exclude
CSS Values and Units Module Level 5	disclose	exclude
CSS Grid Layout Module Level 3	disclose	exclude

Documents not/no longer under the W3C Patent Policy

Document	Patent Disclosure	Patent Exclusion
List of suggested extensions to CSS	disclose	Exclusion is not possible (document not under PP)
Aural Cascading Style Sheets (ACSS) Specification	disclose	Exclusion is not possible (document not under PP)
Behavioral Extensions to CSS	disclose	Exclusion is not possible (document not under PP)
Positioning HTML Elements with Cascading Style Sheets	disclose	Exclusion is not possible (document not under PP)
CSS3 introduction	disclose	Exclusion is not possible (document not under PP)
CSS Mobile Profile 2.0	disclose	Exclusion is not possible (document not under PP)
CSS TV Profile 1.0	disclose	Exclusion is not possible (document not under PP)
User Interface for CSS3	disclose	Exclusion is not possible (document not under PP)
CSS Print Profile	disclose	Exclusion is not possible (document not under PP)
CSS Presentation Levels Module	disclose	Exclusion is not possible (document not under PP)
CSS3 Hyperlink Presentation Module	disclose	Exclusion is not possible (document not under PP)
The CSS ‘Reader’ Media Type	disclose	Exclusion is not possible (document not under PP)
CSS Template Layout Module	disclose	Exclusion is not possible (document not under PP)
Cascading Style Sheets (CSS) Snapshot 2007	disclose	Exclusion is not possible (document not under PP)
CSS Marquee Module Level 3	disclose	Exclusion is not possible (document not under PP)
Requirements for Japanese Text Layout 日本語組版処理の要件(日本語版)	disclose	Exclusion is not possible (document not under PP)
Cascading Style Sheets (CSS) Snapshot 2010	disclose	Exclusion is not possible (document not under PP)
Fullscreen	disclose	Exclusion is not possible (document not under PP)
DOMMatrix interface	disclose	Exclusion is not possible (document not under PP)
Non-element Selectors Module Level 1	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2015	disclose	Exclusion is not possible (document not under PP)
Worklets Level 1	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2017	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2018	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2020	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2021	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2022	disclose	Exclusion is not possible (document not under PP)
CSS Snapshot 2023	disclose	Exclusion is not possible (document not under PP)

Patent Disclosures and Claim Exclusions

This section summarizes patent disclosures by participants in W3C's Cascading Style Sheets (CSS) Working Group as required by section 6 of the W3C Patent Policy.

W3C takes no position regarding either:

• the validity or scope of any intellectual property right or other rights that might be claimed to pertain to the implementation or use of the technology, or
• the extent to which any license under such rights might or might not be available from those not participating in this group.

Where disclosure is required by a W3C Member, the AC Representative makes the disclosure.

Anyone else may also make a disclosure.

Known Disclosures

Disclosures made of claims believed to be essential for the implementation of CSS Mobile Profile 2.0

Disclosures for CSS Mobile Profile 2.0	Licensing	Notes
Issued patent '6209009' (US) held by Openwave Systems Inc. disclosed on 2006-11-28

Disclosures made of claims believed to be essential for the implementation of CSS 2D Transforms

Disclosures for CSS 2D Transforms	Licensing	Notes
Laid-open/published patent application #12/397,325 (US) held by Apple Inc. disclosed on 2009-09-24	Patent Policy Obligations

Disclosures made of claims believed to be essential for the implementation of CSS 3D Transforms Module Level 3

Disclosures for CSS 3D Transforms Module Level 3	Licensing	Notes
Laid-open/published patent application #12/397,325 (US) held by Apple Inc. disclosed on 2009-09-24	Patent Policy Obligations

Disclosures made of claims believed to be essential for the implementation of CSS Animations Level 1

Disclosures for CSS Animations Level 1	Licensing	Notes
Laid-open/published patent application #12/397,325 (US) held by Apple Inc. disclosed on 2009-09-24	Patent Policy Obligations

Disclosures made of claims believed to be essential for the implementation of CSS Transitions

Disclosures for CSS Transitions	Licensing	Notes
Laid-open/published patent application #12/397,325 (US) held by Apple Inc. disclosed on 2009-09-24	Patent Policy Obligations

How to Make a Patent Disclosure

W3C Members and Invited Experts (including those not participating in this group) wishing to disclose a patent for any specification produced by the Cascading Style Sheets (CSS) Working Group should use the Cascading Style Sheets (CSS) Working Group patent disclosure form.

Disclosures from the general public should be sent to the W3C Staff.

For specifications developed under the W3C Patent Policy, parties that commit to the W3C Royalty-Free Licensing Terms are not required to disclose patents. Any party (not just the Working Group Participants) may commit to the W3C Royalty-Free Licensing Terms and may do so by following the instructions in the next section.

Claim Exclusions

Only Cascading Style Sheets (CSS) Working Group participants may exclude patent claims concerning specifications developed under the W3C Patent Policy, per section 4 of the W3C Patent Policy. To make an exclusion, participants should use the Cascading Style Sheets (CSS) Working Group patent claim exclusion form, but only after first disclosing the patent.

Exclusion Opportunities

The Patent Policy FAQ provides detailed information about exclusion opportunities, that is, when a Working Group Participant can exclude a patent claim.

Each exclusion opportunity has a duration. See section 4.1 of the W3C Patent Policy for information on how the exclusion deadline is calculated.

At each exclusion opportunity, Participants may exclude patent claims with respect to a body of text. The Exclusion Draft is the reference body of text for the current exclusion opportunity.

Note: At each new exclusion opportunity (e.g., in the case of a second Candidate Recommendation Snapshot), exclusions are only with respect to differences since the previous reference body of text. These differences may be less than an entire document, and the summary below does not address that granularity. Also, in some edge cases (discussed in the FAQ), Participants, depending on when they joined the Working Group, will have different Exclusion Drafts; the summary below does not reflect this case.

Exclusion Opportunities

CSS Grid Layout Module Level 3

Call for exclusion started on 2024-09-19, opportunity until 2025-02-16

CSS Values and Units Module Level 5

Call for exclusion started on 2024-09-03, opportunity until 2025-01-31

CSS Easing Functions Level 2

Call for exclusion started on 2024-08-29, opportunity until 2025-01-26

CSS Scroll Snap Module Level 2

Call for exclusion started on 2024-07-23, opportunity until 2024-12-20

Additional Licensing Information

As described in section 5 of the W3C Patent Policy:

All Working Group participants are encouraged to provide a contact from which licensing information can be obtained and other relevant licensing information. Any such information will be made publicly available along with the patent disclosures for the Working Group in question.

Patent holders may:

1. Provide additional licensing information for documents produced by this Working Group
2. Provide the same additional licensing information for all documents with associated licensing obligations produced by this Working Group, or
3. Provide additional licensing information for any W3C document with associated licensing obligations produced by any W3C Working Group under the W3C Patent Policy.

Such licensing information should be sent to the W3C Staff.

Please recall that, per section 5 of the W3C Patent Policy, a W3C Royalty-Free license:

may not impose any further conditions or restrictions on the use of any technology, intellectual property rights, or other restrictions on behavior of the licensee, but may include reasonable, customary terms relating to operation or maintenance of the license relationship such as the following: choice of law and dispute resolution.