diff --git a/sermon-a4.css b/sermon-a4.css
index 5e30c76..e3f971c 100644
--- a/sermon-a4.css
+++ b/sermon-a4.css
@@ -1,4 +1,10 @@
 /* @theme sermon-a4 */
+author: simonpipe (codeberg.org/simonpipe/)
+License: MIT
+
+This theme is a derivative work based on:
+"a4-clean.css" by stanfrdb (https://github.com/stanfrbd/A4-marp/tree/main)
+*/
 
 @import 'base';