Update your messenger app. (if seems outdated)
Just send a moon emoji to anyone. Or copy paste this emoji "" then send to any of your chats.
Go on settings and enable dark mode.
Una , I click ang crescent moon emoji () sa any chat nyo.
Then, may magpopop na animation na falling happy crescent moons sa screen.
Balik kayo sa Messenger setting nyo at i toggle yun dark mode.
Voilah! Madilim na po hehe.
Like sa maka appreciate.. Thanks.