diff --git a/app/assets/stylesheets/annotations.scss b/app/assets/stylesheets/annotations.scss
index f15d99c29..38a0f0b4e 100644
--- a/app/assets/stylesheets/annotations.scss
+++ b/app/assets/stylesheets/annotations.scss
@@ -16,6 +16,10 @@
 
 /* annotation modal */
 #annotation-modal {
+  .modal-header {
+    transition: background-color 200ms linear;
+  }
+
   .modal-body {
     display: flex;
   }