Chrome promotes ALL position:fixed elements to GPU compositing layers for scroll
performance, regardless of whether they have animations. The body::before scanline
overlay (position:fixed, z-index:9999, full-viewport) and body::after watermark
(position:fixed) were both on GPU layers. Every CPU repaint from any hover state
change required a compositor re-blend pass → one-frame blink at compositor sync.
Fixes:
- Move scanlines from body::before (position:fixed) into body { background-image }
— same visual, no separate element, no GPU layer promotion
- Set body::before { display:none } and body::after { display:none } in both
dashboard.css and base.css
- Remove animation:matrix-rain from .stat-card:hover::before — background-position
animation is not GPU-composited, caused CPU repaints every frame while hovered
plus GPU texture uploads when animation started/stopped on cursor enter/exit
- Scope a { transition: all } → transition: color in base.css
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Jared Vititoe
ab3e77a9ba