MediaWiki:Citizen.css

:root.skin-citizen-light{
    --color-surface-0: #0b0b0b;
    --color-surface-1: lime;
    --color-surface-2: #fwfwfw;
    --color-surface-3: yellow;
    --color-surface-4: aqua;
    --color-base: blue;
    --color-base--emphasized: lime;
    --color-base--subtle: cornflowerblue;
}

:root.skin-citizen-dark {
    --color-surface-0: #0b0b0b;
    --color-surface-1: #1e1e1e;
    --color-surface-2: #1e1e1e;
    --color-surface-3: #ccdccd;
    --color-surface-4: #339933;
    --color-base: #339933;
    --color-base--emphasized: #65e165;
    --color-base--subtle: #809581;
}