Heuristics for using text-shadow

✓ readable	✗ blurry
dark text & light shadow	dark text & dark shadow
light text & dark shadow	light text & light shadow
gray bg, dark text & light shadow	gray bg, dark text & dark shadow
gray bg, light text & dark shadow	gray bg, light text & light shadow
dark bg, dark text & gray shadow	dark bg, dark text & light shadow
dark bg, light text & dark shadow	dark bg, light text & light shadow