diff --git a/about/about_assets/about.css b/about/about_assets/about.css
index 870b024..dd3b3b4 100644
--- a/about/about_assets/about.css
+++ b/about/about_assets/about.css
@@ -36,6 +36,7 @@ p .aboutTitle {
     clear: both;
 }
 
-summary::-webkit-details-marker {
-  background: none;
+summary {
+    list-style-type: none;
+    cursor: pointer;
 }
\ No newline at end of file
diff --git a/osi_model/osi_model_assets/osi_model.css b/osi_model/osi_model_assets/osi_model.css
index 45fb0ec..8d59e91 100644
--- a/osi_model/osi_model_assets/osi_model.css
+++ b/osi_model/osi_model_assets/osi_model.css
@@ -9,10 +9,6 @@
 }
 
 summary {
-  list-style-image: url(arrow.png);
-}
-
-summary::-webkit-details-marker {
-  background: url(arrow.png);
-  color: transparent;
+    list-style-type: none;
+    cursor: pointer;
 }
\ No newline at end of file