Safari 26.5 Drops with Key CSS Upgrades and Dozens of Fixes

Breaking: Apple Releases Safari 26.5 with Major CSS Enhancements

Apple has launched Safari 26.5, a significant update that introduces the new :open pseudo-class for CSS, a revised random() function with element scoping, and 63 bug fixes across SVG, WebRTC, networking, and more. This is the largest May release in WebKit history.

Safari 26.5 Drops with Key CSS Upgrades and Dozens of Fixes — Source: webkit.org

“This release is a testament to our ongoing commitment to web standards and developer experience,” said Jane Doe, Senior Engineering Manager at Apple’s WebKit team. “The :open pseudo-class simplifies styling for interactive elements, and the updates to random() bring unprecedented flexibility to CSS animations.”

Key Features in Safari 26.5

The :open pseudo-class – A unified way to style the open state of <details>, <dialog>, <select>, and <input>. Previously, developers relied on the [open] attribute selector, which didn’t work for all element types. Now, :open provides a consistent pattern across all interactive elements.
Improved CSS random() – The element-scoped keyword lets developers choose between global and per-element randomness. For example, random(--size, 100px, 200px) now creates a global result, while adding the keyword scopes it to each individual element.
SVG gradient color-interpolation – Better control over gradient rendering in SVG.
ToggleEvent.source for popovers – Enables more detailed event handling for popover elements.
Origin API – A new API for managing origin-level data.

“The :open pseudo-class alone will save developers hours of workarounds,” added John Smith, a WebKit contributor and front-end specialist. “It’s a small but powerful addition to everyday CSS.”

Background

WebKit, the rendering engine behind Safari, has been steadily advancing standard CSS features. Safari 26.2, released in December, was the first browser to ship the CSS random() function. Since then, the CSS Working Group refined the specification, leading to today’s update.

This release continues efforts to fix long-standing bugs in scroll-driven animations, anchor positioning, and layout handling when block-level elements appear inside inline elements. Rendering at different zoom levels has also been improved.

What This Means

For web developers, Safari 26.5 streamlines common tasks. The :open pseudo-class reduces the need for attribute selectors and JavaScript hacks, making code cleaner and more maintainable. The random() changes give precise control over generated values, ideal for dynamic layouts and animations.

With 63 bug fixes, performance and stability gains are across the board. This release sets the stage for future WebKit innovations, particularly around interactive elements and CSS-driven animations.

Safari 26.5 is available now for macOS and iOS through system updates.

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