diff --git a/themes/prism.css b/themes/prism.css
index 618a4121e1..5b8ed2d132 100644
--- a/themes/prism.css
+++ b/themes/prism.css
@@ -106,6 +106,7 @@ pre[class*="language-"] {
 .language-css .token.string,
 .style .token.string {
 	color: #9a6e3a;
+	/* This background color was intended by the author of this theme. */
 	background: hsla(0, 0%, 100%, .5);
 }