Release Notes for Safari Technology Preview 246

Safari Technology Preview 246 brings numerous CSS improvements including support for `color-mix()` with more than two colors, `scroll-state` container type, `font-variant-emoji`, `word-break: auto-phrase`, and the `alpha()` relative color function. Dozens of CSS layout and font rendering bugs are fixed, covering flex layout, subgrid, anchor positioning, and variable fonts. Other highlights include storing FileSystemHandle objects in IndexedDB, popover close watcher integration, SVG `<use>` without fragment identifiers, Origin-Agent-Cluster header support, and fixes across JavaScript, WebRTC, WebGPU, media, scrolling, and Web Inspector.