Shimmer loading placeholder for zer0-mistakes — use while cards, search results, or images are loading, composed into the shape of the content it replaces.

<Skeleton variant="thumbnail" />
<Skeleton variant="title" width="70%" />
<Skeleton variant="text" lines={3} />
<div style=>
  <Skeleton variant="avatar" />
  <Skeleton variant="text" lines={2} width="10rem" />
</div>

Variants: text (multi-line bars, last one 60%), title, button, avatar (circle), thumbnail (4:3). The shimmer is built from --zer0-color-bg-elevated/muted so it reads correctly in both color modes, and it stops under prefers-reduced-motion. Skeletons are aria-hidden — announce loading state separately.