# Safari Technology Preview 255 Release Notes Learn about the latest web technology updates in Safari Technology Preview: Accessibility, Animations, CSS, Editing, Forms, HTML, JavaScript, Media, Networking, Rendering, SVG, Security, Web API, Web Extensions, Web Inspector, WebGL, WebGPU, and WebRTC. ## Overview [Safari Technology Preview](https://webkit.org/blog/6017/introducing-safari-technology-preview/) Release 255 is now [available for download](https://developer.apple.com/safari/resources/) for macOS Golden Gate and macOS Tahoe. If you already have Safari Technology Preview installed, you can update it in System Settings under General → Software Update. This release includes WebKit changes between: [322011@main…323397@main](https://github.com/WebKit/WebKit/compare/b4a444378c79ddb62f086fd2888ddd4cf8d8cdb0...a8755fb056b8fa389e91787f86b8bc5f1919fbce). ### Accessibility #### Resolved Issues - Fixed VoiceOver presses dispatching a `click` event with an `event.detail` of 0. ([322978@main](https://commits.webkit.org/322978@main)) (187732224) - Fixed radio buttons in a group to be exposed as required when the `required` attribute is set on one of the buttons. ([322894@main](https://commits.webkit.org/322894@main)) (189100525) - Fixed list box accessibility children not updating when options are added or removed. ([323117@main](https://commits.webkit.org/323117@main)) (189412211) ### Animations #### Resolved Issues - Fixed `getComputedStyle()` ignoring the pseudo-element when checking whether a property is being animated. ([322681@main](https://commits.webkit.org/322681@main)) (188502400) - Fixed `requestAnimationFrame()` handles to use the full unsigned long range defined by the IDL. ([322922@main](https://commits.webkit.org/322922@main)) (189270148) - Fixed view transition setup to flush the update callback queue. ([323173@main](https://commits.webkit.org/323173@main)) (189533643) ### CSS #### New Features - Added support for CSS module scripts, allowing a stylesheet to be imported from JavaScript using `import sheet from "./styles.css" with { type: "css" }`. ([322887@main](https://commits.webkit.org/322887@main)) (80917329) #### Resolved Issues - Fixed `font-family: initial` acting like `font-family: inherit` instead of resolving to the initial value. ([322304@main](https://commits.webkit.org/322304@main)) (54306281) - Fixed `box-sizing: content-box` being ignored for percentage-height tables (`display: table`), which caused vertical padding to be dropped. ([322812@main](https://commits.webkit.org/322812@main)) (122587242) - Fixed `min-width: max-content` being ignored for the min-content contribution of a percentage-width replaced element. ([322974@main](https://commits.webkit.org/322974@main)) (179947068) - Fixed the top color extension to use relative colors with filters when applicable. ([323153@main](https://commits.webkit.org/323153@main)) (186098400) - Fixed `Range.getBoundingClientRect()` returning empty rects for content inside a `content-visibility: hidden` subtree. ([323204@main](https://commits.webkit.org/323204@main)) (186165755) - Fixed elements using a background image that depends on `currentColor` not repainting when the current color changes. ([323240@main](https://commits.webkit.org/323240@main)) (188036420) - Fixed subgrid implicit grid-area line names being matched by the first substring instead of the suffix. ([322238@main](https://commits.webkit.org/322238@main)) (188203288) - Fixed tree-scoped `var()` and custom function references inside an `@function` failing to resolve when the function is called from a `:host` rule. ([322679@main](https://commits.webkit.org/322679@main)) (188206030) - Fixed an issue where duplicate `anchor-name` values among `` elements in a spatial portal resolved unpredictably. ([322709@main](https://commits.webkit.org/322709@main)) (188209540) - Fixed `@scope` so that structural DOM changes correctly invalidate scope membership when the scoping root selector depends on them. ([322680@main](https://commits.webkit.org/322680@main)) (188398757) - Fixed `revert` inside `@starting-style` dropping `@starting-style` declarations from lower cascade layers. ([322688@main](https://commits.webkit.org/322688@main)) (188463947) - Fixed the `rotate` property to preserve the sign of the axis when serializing. ([322682@main](https://commits.webkit.org/322682@main)) (188493811) - Fixed `revert` and `revert-layer` using the wrong cascade origin for visited and unvisited link styles, which wrongly disabled native appearance. ([323205@main](https://commits.webkit.org/323205@main)) (188494505) - Fixed `getComputedStyle()` serializing the `overscroll-behavior` shorthand as a single value of the larger axis instead of both axis values. ([322685@main](https://commits.webkit.org/322685@main)) (188534035) - Fixed block-axis multicolumn content being painted at the wrong offset when the column set does not start at the top of the multicol container. ([322687@main](https://commits.webkit.org/322687@main)) (189067503) - Fixed `shape-margin` values above `65535px` on an image `shape-outside` producing a much smaller float area. ([322727@main](https://commits.webkit.org/322727@main)) (189069223) - Fixed a `line-clamp` container to establish an independent formatting context. ([322767@main](https://commits.webkit.org/322767@main)) (189090409) - Fixed replaced elements ignoring `aspect-ratio` when both `width` and `height` are `auto`. ([322745@main](https://commits.webkit.org/322745@main)) (189096923) - Fixed the `line-clamp` block ellipsis being placed after a `` in a `white-space: nowrap` line. ([322758@main](https://commits.webkit.org/322758@main)) (189103913) - Fixed an overflowing preserved tab not wrapping to the next line. ([322759@main](https://commits.webkit.org/322759@main)) (189104880) - Fixed the `line-clamp` block ellipsis not hanging with `hanging-punctuation`. ([322772@main](https://commits.webkit.org/322772@main)) (189105782) - Fixed `text-overflow` truncating a `unicode-bidi: plaintext` line in the wrong direction. ([322866@main](https://commits.webkit.org/322866@main)) (189108555) - Fixed an image `shape-outside` dropping an above-threshold run that starts in the last column. ([322756@main](https://commits.webkit.org/322756@main)) (189116534) - Fixed `line-clamp: auto` not being able to clamp between sibling blocks. ([322836@main](https://commits.webkit.org/322836@main)) (189124610) - Fixed `line-clamp: auto` clamping inside a box with a set height. ([322842@main](https://commits.webkit.org/322842@main)) (189138321) - Fixed the `line-clamp` block ellipsis being placed on a line that only contains a float. ([322791@main](https://commits.webkit.org/322791@main)) (189151667) - Fixed the baseline of an empty MathML `` element to account for `border-top` and `padding-top`. ([322826@main](https://commits.webkit.org/322826@main)) (189209081) - Fixed CSS grid intrinsic width computation to resolve `auto-fill` repetitions against the grid container’s minimum and maximum size. ([322848@main](https://commits.webkit.org/322848@main)) (189223527) - Fixed CSS grid column sizing to resolve percentage rows against the block size rather than the inline size when estimating row sizes. ([322850@main](https://commits.webkit.org/322850@main)) (189230010) - Fixed grid container minimum and maximum sizes to respect `box-sizing: border-box`. ([322856@main](https://commits.webkit.org/322856@main)) (189235347) - Fixed a percentage-width child of a vertical writing mode box to keep following the box’s width after a style change. ([322964@main](https://commits.webkit.org/322964@main)) (189316242) - Fixed `cross-fade()` to match the CSS Images Level 4 specification and the behavior of other browsers. ([322918@main](https://commits.webkit.org/322918@main)) (189356185) - Fixed grid layout to return the grid’s used block size, so the container’s size is correct once layout is complete. ([323053@main](https://commits.webkit.org/323053@main)) (189357098) - Fixed grid containers to resolve percentage and `calc()` values for `min-width`, `max-width`, `min-height` and `max-height`. ([323051@main](https://commits.webkit.org/323051@main)) (189358198) - Fixed `:visited` style not updating for links inside shadow trees. ([323396@main](https://commits.webkit.org/323396@main)) (189380898) - Fixed baseline alignment of grid items so it is applied after the items have been sized. ([323238@main](https://commits.webkit.org/323238@main)) (189457596) - Fixed `attr()` to avoid an unnecessary legacy code path in simple cases. ([323098@main](https://commits.webkit.org/323098@main)) (189485680) - Fixed `MediaList` writes being silently dropped after the owning rule or stylesheet is destroyed. ([323203@main](https://commits.webkit.org/323203@main)) (189496021) - Fixed collapsed SVG shapes and images being painted when `visibility: collapse` should be treated as `hidden`. ([323110@main](https://commits.webkit.org/323110@main)) (189496450) - Fixed block boxes after the `line-clamp` clamp point remaining visible. ([323220@main](https://commits.webkit.org/323220@main)) (189543433) - Fixed content before the `line-clamp` clamp point losing its lines when it does not change. ([323225@main](https://commits.webkit.org/323225@main)) (189569400) - Fixed block boxes after the `line-clamp` clamp point still taking up space. ([323253@main](https://commits.webkit.org/323253@main)) (189570948) - Fixed floats after the `line-clamp` clamp point remaining visible. ([323337@main](https://commits.webkit.org/323337@main)) (189578173) - Fixed `adoptedStyleSheets` continuing to apply removed sheets after its length is shrunk, and ignoring changes to a sheet after its duplicate is removed. ([323233@main](https://commits.webkit.org/323233@main)) (189579103) - Fixed an implicit `@scope` rule in a constructed stylesheet adopted by a document matching nothing. ([323237@main](https://commits.webkit.org/323237@main)) (189584948) - Fixed floats making the `line-clamp` container taller. ([323349@main](https://commits.webkit.org/323349@main)) (189630233) - Fixed floats adding to the scrollable overflow of the `line-clamp` container. ([323353@main](https://commits.webkit.org/323353@main)) (189641420) - Fixed `line-clamp: auto` containers having no line clamp until the clamp point is found. ([323357@main](https://commits.webkit.org/323357@main)) (189652879) - Fixed floats painting past the block-end content edge of the `line-clamp` container. ([323390@main](https://commits.webkit.org/323390@main)) (189653161) - Fixed container size queries truncating fractional container sizes to integers. ([323328@main](https://commits.webkit.org/323328@main)) (189653185) - Fixed absolutely positioned elements whose containing block is an inline after the `line-clamp` clamp point remaining visible. ([323395@main](https://commits.webkit.org/323395@main)) (189671905) ### Editing #### Resolved Issues - Fixed `DataTransfer` treating any format that merely starts with `text/plain`, such as `text/plainfoo`, as `text/plain`. ([322954@main](https://commits.webkit.org/322954@main)) (189265567) ### Forms #### New Features - Added support for `` in the native appearance of ``. ([322716@main](https://commits.webkit.org/322716@main)) (178876621) #### Resolved Issues - Fixed `:open` no longer matching a `` whose base appearance picker is still showing. ([322666@main](https://commits.webkit.org/322666@main)) (188911581) - Fixed a `` element computing its selected option’s style from outdated ancestor styles. ([322665@main](https://commits.webkit.org/322665@main)) (189109118) - Fixed a vertical range slider fill overshooting its value when tick marks are present and the thumb is hidden. ([322780@main](https://commits.webkit.org/322780@main)) (189116567) ### HTML #### Resolved Issues - Fixed a `