Slider was computing mid = (0 - 10) / (60 - 10) * 100 = -20% for VIX
(0 outside the 10-60 range), causing the colored track to start at a negative
left position and overflow the container.
Fix: add overflow-hidden on the track div; add center prop (defaults 0)
that the caller sets to the actual baseline value when 0 is out of range.
VIX now pivots at 18, real yield US at 2.1.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
c36f11ad32