• Home Blog New to the web platform in DecemberStay organized with collectionsSave and categorize content based on your preferences. • Discover some of the interesting features that have landed in stable and beta web browsers during December 2025. • Rachel AndrewGitHubLinkedInMastodonBlueskyHomepage Published: December 16, 2025 Published: December 16, 2025 Stable browser releases Chrome 143,Firefox 146andSafari 26.2released to stable during December. • This post takes a look at the many new features this month, with several things becoming Baseline Newly available. • The@scopeCSS at-rule is now Baseline Firefox 146 includes the@scopeCSS at-rule which lets you select elements in specific DOM subtrees. • Define a scope inside which selectors can target elements, and you avoid overly specific and lengthy selectors.
Article Summaries:
- In December 2025, major browsers added several new baseline features. Chrome 143 introduced the font‑language‑override property, @container anchored(fallback) queries, and side‑relative syntax for background‑position‑x/y. Firefox 146 shipped the CSS @scope at‑rule, contrast‑color() function, and the text‑decoration‑inset property. Safari 26.2 added the animation overallProgress read‑only property, baseline support for LCP and INP metrics via the Contentful Paint and Event Timing APIs, and CHIPS (Cookies Having Independent Partitioned State). These updates expand styling control, accessibility, performance measurement, and privacy across the web platform.
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