Created attachment 455658 [details] Chrome TP 142 Open https://jec.fyi/demo/css-container-queries in Chrome and Safari, and compare. A few issues: 1. The initial view is different. Expected Chrome view. 2. Try to resize the container (white box) horizontally by dragging the triangle in the container's right bottom corner. Not able to resize it in Safari. Chrome: https://imgur.com/qTe0po6 Safari: https://imgur.com/dl7ooAP
<rdar://problem/90799512>
The test page uses obsolete syntax. The current spec interpretion of @container size (max-width: 399px) { is "match nearest width container that has name "size" and width <= 399px. There is no container with that name so nothing is matched. Note that the current STP doesn't yet implement this fully though the trunk should.