Baseline expands with the Web Platform Dashboard and a cross-browser feature update
At Google I/O, the Baseline project announced two major steps forward: a new Web Platform Dashboard for tracking the web platform and features as they move toward interoperability, plus integrations with RUM Archive and an upcoming integration with RUMvision. The dashboard provides a way to view the whole web platform and track individual features on their way to becoming part of Baseline. The RUM Archive integration extends Baseline into real-world usage data, with more tooling partners to follow.
Twelve features now cross-browser
Alongside those announcements, twelve web platform features have reached Baseline Newly available status, meaning they now work across Chrome, Edge, Firefox, and Safari. The list spans CSS layout and styling, HTML semantics, form UX, and stream processing.
CSS container queries and subgrid
Size container queries let components respond to the inline-size of their container rather than the viewport, making it possible to build reusable components that adapt to available space. The feature was newly available in February 2023 and widely available in August 2025. Subgrid, meanwhile, allows nested grids to inherit the tracks of a parent grid for better alignment. It was newly available in December 2023 and widely available in June 2026.
The :has() selector
Long requested as a "parent selector," the relational :has() pseudo-class selects an element based on its contents, enabling single components that adapt to what they contain. Newly available in December 2023, it became widely available in June 2026 alongside subgrid.
CSS Nesting and color-mix()
CSS Nesting brings preprocessor-style selector nesting into the platform, reducing repetition and grouping related rules. It was newly available in August 2023 and widely available in February 2026. The color-mix() function mixes two colors in any available color space, including the newer LCH, Lab, OKLCH, and OKLab models. It reached newly available status in April 2023 and wide availability in October 2025.
The <search> element and responsive video
The HTML <search> element provides a semantic container for search or filtering functionality on a page. Newly available in October 2023, it became widely available in April 2026. Responsive video works similarly to responsive images: the <source> element inside <video> can serve device-appropriate video. That feature shipped across browsers between November 2023 and May 2026.
The inert attribute and user-form pseudo-classes
Applying the inert attribute stops clicks, focus, and assistive-technology exposure for an element and its subtree—useful for background content behind dialogs, among other cases. It was newly available in April 2023 and widely available in October 2025. The :user-valid and :user-invalid pseudo-classes differ from the older :valid and :invalid by only matching after user interaction has happened, so required fields don't show error styling before they are touched. They went from newly available in October 2023 to widely available in April 2026.
Compression Streams, Declarative Shadow DOM, and the Popover API
The Compression Streams API provides built-in data compression for streams, removing the need to bundle a compression library for tasks like creating zip downloads. It was newly available in May 2023 and widely available in November 2025. Declarative Shadow DOM creates shadow trees from HTML rather than only from JavaScript via attachShadow(), which matters for server-side rendering and JavaScript-free environments like email clients. It reached newly available in February 2024 and wide availability in August 2026. The Popover API adds a native mechanism for decorative popups used by menus, custom toasts, and content pickers. It became newly available in April 2024 and widely available in October 2026.
These twelve features are a sample of what has moved into Baseline Newly available. The full lists of features that became part of Baseline 2023 and Baseline 2024 continue to grow on the Baseline site.
