The Wikidata .wikibase-copyrightnotification-container popup message (that appears when the user is not logged in and start to add a Wikidata statement, clicking add statement) is not compatible with dark-mode. It should adapt itself to be shown like the second image.

1. light popup on dark background	2. dark popup on dark background

I styled the latter image on-the-fly adding filter: invert(.5) to the .tipsy-arrow class and the following css rules for the .tipsy-inner one.

background-color: var(--background-color-interactive);
color: inherit;
border: var(--border-color-base);