Remove all lightness shifts — background stays at L=0.20-0.23 throughout
with light text (L=0.86-0.88) the entire page. No more bg brightening or
fg flipping. Hue drifts gently through greens and teals (130-175) for a
ferny forest floor feel. Canvas trail fade updated to green tint.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>