Urgent: Apple Releases Safari 26.5 – CSS :open Pseudo-Class and 63 Patches Land
Apple has officially rolled out Safari 26.5, a significant update to its flagship browser that introduces the long-anticipated CSS :open pseudo-class, refined random() function capabilities, SVG gradient improvements, and a massive bug-fix haul. The release, described by the WebKit team as the largest May update in the engine’s history, addresses 63 issues spanning SVG, WebRTC, networking, editing, and rendering at varied zoom levels.
CSS :open Pseudo-Class: A Unified Way to Style Interactive Elements
Developers can now use the :open pseudo-class to target the open state of elements such as <details>, <dialog>, <select>, and <input>. Previously, this required attribute selectors like [open], which only worked on <details> and <dialog> and failed on <select> or <input>.
“The :open pseudo-class provides a single, consistent pattern across all these element types,” said a WebKit spokesperson. “It’s a practical improvement that simplifies everyday CSS.” For instance, select:open { border: 1px solid skyblue; } now highlights a dropdown when it expands. The feature degrades gracefully: unsupporting browsers simply ignore the rule, leaving functionality intact.
CSS random() Gets an Element-Scoped Keyword
Following its initial random() implementation in Safari 26.2, this update aligns with the latest CSS Working Group specification. Named random values, such as random(--size, 100px, 200px), now produce a global result rather than per-element values. For per-element behavior, developers can use the new element-scoped keyword.
“This change gives authors precise control over random generation,” the spokesperson explained. “If you want eight boxes to share the same random size, you use a named value; if you want all unique, you skip the name.” The update also includes fixes for color-interpolation in SVG gradients, ensuring smoother visual transitions.
Additional Features: Origin API and ToggleEvent.source
Safari 26.5 introduces the Origin API, giving web applications more granular control over origin-related data. The ToggleEvent.source property for popovers is now available, allowing developers to identify the element that triggered a popover toggle. These additions enhance interactivity and security.
Background
WebKit is the open-source rendering engine powering Safari. The team has been steadily improving its feature set and stability, with this release representing a culmination of months of work. The 63 bug fixes include enhancements to scroll-driven animations, anchor positioning, and layout handling when block-level elements appear inside inline elements.
What This Means
For web developers, Safari 26.5 reduces friction in styling interactive components and expands creative possibilities with CSS random(). The dozens of bug fixes improve cross-browser consistency and performance, especially for complex layouts and animations. As Apple continues to align with evolving web standards, this update ensures Safari remains competitive for modern web applications.