Scroll markers

Description

Prior requests : #1131

Description

Scroll containers have evolved beyond carousel pagination and other scrollable interfaces and are now capable of providing interfaces for tabs and wizards as demonstrated at Chrome Carousel Gallery .The ::scroll-marker and ::scroll-marker-group pseudo-elements provide native, styleable navigation for scroll containers.

Today, developers treat these patterns as separate components, often implementing and managing each one with JavaScript. Making scroll markers interoperable would allow them to share a common browser-managed primitive. It would also reduce the accessibility problems caused by repeatedly reimplementing the same interaction patterns.

Specification

https://drafts.csswg.org/css-overflow-5/#scroll-markers

web-feature

https://web-platform-dx.github.io/web-features-explorer/features/scroll-markers/

Test Links

https://wpt.fyi/results/css/css-overflow?label=master&label=experimental&aligned&q=scroll-marker

Additional Signals

Standards Positions:

Mozilla: https://github.com/mozilla/standards-positions/issues/1161
WebKit: https://github.com/WebKit/standards-positions/issues/447

Start by reviewing the existing scroll-marker results under css/css-overflow on the linked WPT dashboard and compare them with the CSS Overflow 5 scroll-markers specification. Add the missing interoperability coverage for ::scroll-marker and ::scroll-marker-group, then verify the relevant tests report consistently across implementations.