Previewers: Ensure popup is visible across themes (#3080)
diff --git a/plugins/previewers/prism-previewers.css b/plugins/previewers/prism-previewers.css
index b36988c..2d5e957 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;