diff --git a/kallithea/public/css/style.css b/kallithea/public/css/style.css
--- a/kallithea/public/css/style.css
+++ b/kallithea/public/css/style.css
@@ -1,3 +1,12 @@
+/*!
+ * Don't edit the css file directly.
+ *
+ * Instead, edit the less file(s) and regenerate the css:
+ *
+ * npm --prefix kallithea/public/less install
+ * npm --prefix kallithea/public/less run less
+ *
+ */
 body {
   background: url("../images/background.png") repeat scroll 0 0 #B0B0B0;
   font-family: Lucida Grande, Verdana, Lucida Sans Regular, Lucida Sans Unicode, Arial, sans-serif;
diff --git a/kallithea/public/less/style.less b/kallithea/public/less/style.less
--- a/kallithea/public/less/style.less
+++ b/kallithea/public/less/style.less
@@ -1,3 +1,13 @@
+/*!
+ * Don't edit the css file directly.
+ *
+ * Instead, edit the less file(s) and regenerate the css:
+ *
+ * npm --prefix kallithea/public/less install
+ * npm --prefix kallithea/public/less run less
+ *
+ */
+
 body {
   background: url("../images/background.png") repeat scroll 0 0 #B0B0B0;
   font-family: Lucida Grande, Verdana, Lucida Sans Regular, Lucida Sans Unicode, Arial, sans-serif;