This Resource Pack will change minecraft's lighting to show where monsters can and can't spawn. Don't forget to enable "Custom Color" in Video Settings > Quality > Custom Colors: ON
(You may need to restart the game.)
/!\In 1.18+ mobs only spawn at a light level of 0/!\

RED = Dangerous: All monsters can spawn here.

BLUE = Very Safe: All mobs that rely on light-levels cannot spawn here.

/!\With Optifine change option "smooth lightning" to off for more precision/!\ 