Index: wp-content/themes/twentyten/editor-blocks.css
===================================================================
--- wp-content/themes/twentyten/editor-blocks.css	(revision 54560)
+++ wp-content/themes/twentyten/editor-blocks.css	(working copy)
@@ -368,3 +368,10 @@
 :root .editor-styles-wrapper .has-white-background-color:visited {
 	background-color: #fff;
 }
+
+/* Inserter Icon */
+
+.editor-styles-wrapper .block-editor-inserter path {
+    	color: #ffffff;
+}
+