Bug: placeholder image backgrounds broken due to invalid CSS in @unpic/placeholder

[mhwinkler]

We discovered that the component's blurhash background image previews aren't rendering at all in the latest Chrome browser (ref EmDashImage.astro). This is because the inline background style was being silently discarded by the browser as invalid CSS.

Root cause: @unpic/placeholder's blurhashToImageCssString returns background: url("...") cover, which is invalid shorthand. The CSS spec requires background-position before /background-size, e.g. center/cover.

For visibility, I've opened a fix upstream: ascorbic/unpic-placeholder#18

In our case, a pnpm patch generated with Claude was able to temporarily resolve it.

[marcusbellamyshaw-cell]

Confirmed still live on current main: EmDashImage.astro still calls blurhashToImageCssString directly with no sanitizing (packages/core/src/components/EmDashImage.astro), and emdash is still pinned to @unpic/placeholder@^0.1.2, which doesn't have your upstream fix (ascorbic/unpic-placeholder#18 is still open/unmerged). So this is real and unfixed today, not just historical.

Since ascorbic maintains both repos, the cleanest path is probably getting #18 merged/released upstream and bumping the pin here — but if you want a stopgap sooner, splitting the returned shorthand into background-image/background-size (or reordering the shorthand: background: url("...") center / cover) at the call site in EmDashImage.astro avoids waiting on the upstream release. Worth pinging @ascorbic on the upstream PR directly, or opening a PR here with the call-site workaround if you want a faster fix landed in emdash itself.