diff --git a/static/themes/default/css/plinth.css b/static/themes/default/css/plinth.css
index 2f5415ce3..4062f916d 100644
--- a/static/themes/default/css/plinth.css
+++ b/static/themes/default/css/plinth.css
@@ -1,3 +1,7 @@
+/*
+# SPDX-License-Identifier: AGPL-3.0-or-later
+*/
+
 @font-face {
     font-family: 'Lato';
     src: url('../lato/Lato-Italic.woff2') format('woff2');
diff --git a/static/themes/default/css/responsive.css b/static/themes/default/css/responsive.css
index d44437216..7c772c62b 100644
--- a/static/themes/default/css/responsive.css
+++ b/static/themes/default/css/responsive.css
@@ -1,4 +1,6 @@
-
+/*
+# SPDX-License-Identifier: AGPL-3.0-or-later
+*/
 /* Responsive queries */
 /* Smartphone */