I finally got round to implementing dark mode for this site (the cobbler’s children have no shoes and all that…) Here’s all the CSS I had to add: @media (prefers-color-scheme: dark) { /* Invert all elements on the body while attempting to not alter the hue substantially. */ body { filter: invert(100%) hue-rotate(180deg); } /* Workarounds and optical adjustments. */ /* Firefox workaround: Set the background colour for the html element separately because, unlike other browsers, Firefox doesn’t apply the filter to the root element’s background.