diff --git a/css/highlighting.css b/css/highlighting.css
index 87144f68..66c72033 100644
--- a/css/highlighting.css
+++ b/css/highlighting.css
@@ -7,7 +7,7 @@ code[class*=language-],
 pre[class*=language-] {
 	font-family: var(--font-family-code);
 	background-color: var(--color-bg-alt);
-	font-size: .9rem;
+	font-size: .9em;
 	text-shadow: 0 1px var(--color-shadow);
 	-moz-tab-size: 4;
 	-o-tab-size: 4;