MediaWiki:Citizen.css

/* All CSS here will be loaded for users of the Citizen skin */
:root.skin-citizen-dark {
	--color-primary__h: 41;
	--color-primary__s: 100%;
	--color-primary__l: 50%;
	
	--background-color: 0;
    --color-surface-0: hsl(--background-color,0%,5%);
    --color-surface-1: hsl(--background-color,0%,12%);
    --color-surface-2: hsl(--background-color,0%,15%);
    --color-surface-3: hsl(--background-color,0%,20%);
    --color-surface-4: hsl(--background-color,0%,25%);
}

.skin-citizen-dark #siteSub {
	display: none;
}