Apply to new .theme--dark class

Signed-off-by: Julius Härtl <jus@bitgrid.net>

src/components/cards/CardItem.vue

@@ -150,6 +150,7 @@ export default {
 	@import './../../css/animations';
 	@import './../../css/variables';
 
+	body.theme--dark .card,
 	body.dark .card {
 		border: 1px solid var(--color-border);
 	}