diff --git a/wp-includes/js/tinymce/skins/wordpress/wp-content.css b/wp-includes/js/tinymce/skins/wordpress/wp-content.css
index 963e864095..96fed744df 100644
--- a/wp-includes/js/tinymce/skins/wordpress/wp-content.css
+++ b/wp-includes/js/tinymce/skins/wordpress/wp-content.css
@@ -264,9 +264,6 @@ audio {
 	width: 1px;
 	background-color: black;
 	background-color: currentcolor;
-	-webkit-transition: opacity 0.15s ease-out;
-	-moz-transition: opacity 0.15s ease-out;
-	transition: opacity 0.15s ease-out;
 	opacity: 1;
 }