CSS quotes property - support 'auto' value

Category: CSS
Type: New or changed feature
Status: Enabled by default (Chrome 87)
Intent stage: Shipped

Breaking change: No
Enterprise impact: None
Spec maturity: Working draft
Web Platform Tests: Yes

WPT details: http://wpt.fyi/css/css-content/inheritance.html http://wpt.fyi/css/css-content/quotes-033.html http://wpt.fyi/css/css-typed-om/the-stylepropertymap/properties/quotes.html

Summary

Support 'auto' for the 'quotes' property. CSS2 specified the initial value for 'quotes' as UA dependent, but WebKit and Blink returns an invalid value (empty string) which will not round-trip. Setting it to the empty string will remove the declaration instead of setting it to the initial value. css-content-3 instead uses an 'auto' keyword for the default UA behavior.

Motivation

Fix brokenness in current implementation and align with spec and Firefox.

Standards & signals

Specification: https://www.w3.org/TR/css-content-3/#quotes
Firefox: Shipped/Shipping — Shipped in Firefox 70 according to MDN.
Safari: Shipped/Shipping — Not responded to reported issue: https://bugs.webkit.org/show_bug.cgi?id=215646
Web developers: No signals
Tracking bug: https://crbug.com/990557

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=css%2Fcss-content
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+CSS%20quotes%20property%20-%20support%20'auto'%20value
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=CSS%20quotes%20property%20-%20support%20'auto'%20value
Baseline status: https://webstatus.dev/?q=CSS%20quotes%20property%20-%20support%20'auto'%20value

View on chromestatus.com