You could just use the filter tool to change the brightness of the whole scene.
So for example:
@set hsl 0 0 -43 in 0
And if you want to reset it back to normal:
@reset hsl in 0
You could just use the filter tool to change the brightness of the whole scene.
So for example:
@set hsl 0 0 -43 in 0
And if you want to reset it back to normal:
@reset hsl in 0