The #f6f6f4 off-white background was showing through the 30px grid
gaps and behind translated cards during the zoom/unzoom transitions,
creating visible white strips in the rendered video. Changed to
#1a1a20 (near-black) so gaps read as intentional dark separators.
Also added a .zoom-backdrop div behind the grid in the zoom demo that
fades to the focus card's gold gradient during the transition, covering
any gaps left by sibling cards translating off-screen.
Co-authored-by: Kanyini <onebenson@gmail.com>