Blur the background when displaying modals

themes/tiddlywiki/snowwhite/base.tid

@@ -541,6 +541,10 @@ canvas.tw-edit-bitmapeditor  {
 ** Modals
 */
 
+.tw-modal-displayed {
+	-webkit-filter: blur(4px);
+}
+
 .modal-backdrop {
 	position: fixed;
 	top: 0;