View Transitions are a powerful Modern Web feature allow for smooth seamless animated transitions two between different states of a web page. They can make for a much more pleasant user experience, but as with any new web platform feature, browser support is not yet fully universal so you need to add some fallback logic to your code.view-transitions-mock bridges that gap. It is a spec-compliant JavaScript implementation of Same-Document View Transitions that polyfills the entire JavaScript API surface of the spec, but that doesn’t do the animation bits.

CSS Anchor Positioning is a powerful tool, but one of the things that you cannot do natively (yet) is animating the position-area property. This blog post introduces a technique to animate position-area changes using View Transitions.

Talk on CSS Anchor Positioning

Vertical Tabs are available behind a flag in Chrome 145 (current beta)

From Chrome 145 onwards, 100vw will automatically subtract the size of the (vertical) scrollbar from it if you have forced the html element to always show a vertical scrollbar (using overflow[-y]: scroll) or if you reserve space for it (using scrollbar-gutter: stable). The same applies to vh with a horizontal scrollbar, as well as all small, large, and dynamic variants.

If you read the Safari release notes – like the Safari 26.2 release notes – you see a lot of trailing “(12345678)”-mentions in the list of fixed bugs. These numbers are Apple-internal bug IDs, as used within Apple’s internal bug tracker (fka?) named “Radar”.These numbers are not linked to anything because Radar is Apple-internal, so to external people these numbers are practically useless … or are they?

We have Scroll-Driven Animations. Now say hi to Scroll-Triggered Animations.

Once again, it has been an AMAZING year for CSS and UI. To celebrate this, we – the Chrome CSS/UI DevRel Team – created another edition of CSS Wrapped!

As an experiment to see if Modern CSS is up to the task, I recreated the Google Antigravity website with Modern CSS.

If you kinda understand Anchor Positioning, but it still surprises you from time to time, then most likely this is the missing piece of information: the Inset-Modified Containing Block (or IMCB for short).