What does "@custom-variant dark (&:is(.dark *));" do?

[Toshimichi0915]

When I create a new shadcn project by pnpm dlx shadcn@latest init, globals.css is created with the following line:

@import "tailwindcss";
@plugin "tailwindcss-animate";
@custom-variant dark (&:is(.dark *));

...

@custom-variant annotation is something I don't understand, and when I look it up on the Internet, few results show up.

What is @custom-variant, exactly?

[GauthierPLM]

It's a native feature of TailwindCSS for handling dark mode: https://tailwindcss.com/docs/dark-mode#toggling-dark-mode-manually

[danon]

@GauthierPLM The documentation you linked is very limited. There's merely one paragraph about @custom-variant dark.