diff --git a/doc/style.css b/doc/style.css
index b98507991..246da1ffc 100644
--- a/doc/style.css
+++ b/doc/style.css
@@ -146,6 +146,10 @@ div.recentchanges {
 	margin-top: 1em;
 }
 
+.error {
+	color: #C00;
+}
+
 /* Used for invalid form fields. */
 .fb_invalid {
 	color: red;