diff --git a/plugins/previewers/prism-previewers.css b/plugins/previewers/prism-previewers.css
index b36988c2bf..2d5e9570c0 100644
--- a/plugins/previewers/prism-previewers.css
+++ b/plugins/previewers/prism-previewers.css
@@ -13,6 +13,7 @@
 	width: 32px;
 	height: 32px;
 	margin-left: -16px;
+	z-index: 10;
 
 	opacity: 0;
 	-webkit-transition: opacity .25s;