A JS file for Tampermonkey that allows you to enable dark theme on Whatsapp Web website.
< Feedback on Whatsapp Web dark theme enabler
Carpenter Dominic thanks for feedback! This script just enables dark theme built-in the app, that's it. It doesn't have its own stylesheet.
Developers of Whatsapp just didn't place the toggle to enable dark theme, nobody knows why.
Firefox 77.0b9 (64-bit), Microsoft Windows 10.0.18363.836, WhatsApp Messenger (Beta) 2.20.157 - OK. However, it is a pity that the topic is dark, not black. That is, the predominant colors are dirty green, gray.