Module:table of contents/style.css

@media screen {
	html.skin-theme-clientpref-night .toc,
	html.skin-theme-clientpref-night .toc th,
	html.skin-theme-clientpref-night .toc td {
		border-color: #72777d; /* var(--border-color-base, #72777d); */
	}
}
@media screen and (prefers-color-scheme: dark) {
	html.skin-theme-clientpref-os .toc,
	html.skin-theme-clientpref-os .toc th,
	html.skin-theme-clientpref-os .toc td {
		border-color: #72777d; /* var(--border-color-base, #72777d); */
	}
}