light-dark is not working for light mode

[elfin flicker]

I don't know why when I use light-dark in the css modules, whenever it's light mode it doesn't work, but if it's in dark mode it does:

    background-colour: light-dark(red, blue);
}

The alternative that worked for me was to use it like this:

@mixin light {
        background-colour: red;
    }
    
      @mixin dark {
        background-colour: blue;
    }

I don't know why light-dark doesn't work

[glacial breach]

It's background-color, not background-colour