Focusing the textarea while it had an error drew two red curves down its
left side, a couple of pixels apart. Not a positioning problem -- the
ring and the outline share the same box to the pixel. It is clamping.
The outline's leading piece is 12px wide, so the 20px corner radius it
was given got clamped to 12, while the focus ring, drawn across the full
width, kept a true 20px curve. Same declared radius, two different
curves. At 10px nothing is clamped and they land on top of each other.
The single-line fields never showed this: at 999px both the outline and
the ring clamp to half the field's height, so they already agreed.
Verified at 2x: one continuous outline, ring and leading piece both
reporting 10px.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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