The positive outline-offset from the previous fix pushed the highlight
outside the element's own box — which gets clipped by the first
overflow:hidden ancestor (the canvas itself, or a rounded-corner
container) on whichever sides touch that ancestor's edge. A row of
gauges flush against the top/left of its container showed only a
stray line on the untouched side instead of a full frame.
Switch to an inset box-shadow: it always stays inside the element's own
box, so it can never be clipped by an ancestor, and it naturally follows
the element's own border-radius.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
