Dan Mode: pure white backgrounds, electric blue text (#0000ff), nuclear
yellow accents (#ffff00), hot magenta borders (#ff00ff), red labels,
glowing box-shadows. Maximum saturation. Hostile to human vision by design.
Theme toggle now cycles light → dark → dan → light (icons: 🌙😎☀️).
PICO_CSS.md: documents [role=button] color clobber, palette scoping rules,
and theme toggling pattern for future reference.
