overflow:hidden on direct children of preserve-3d flattens the 3D
context in Chrome, causing backface-visibility:hidden to fail.
Move border-radius + overflow to inner wrapper divs (.card-front-inner,
.card-back-inner) and keep the face elements themselves free of those
properties. Also add -webkit-backface-visibility:hidden and
will-change:transform for consistent GPU compositing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>