Index: wp-content/themes/twentysixteen/css/editor-style.css
===================================================================
--- wp-content/themes/twentysixteen/css/editor-style.css	(revision 54300)
+++ wp-content/themes/twentysixteen/css/editor-style.css	(working copy)
@@ -539,3 +539,18 @@
 .rtl table caption {
 	text-align: right;
 }
+.wp-block-search__text-button.alignright {
+    float: none;
+}
+
+.wp-block-search__text-button.alignright .wp-block-search__inside-wrapper {
+    margin:0 0 0 auto;
+}
+
+.wp-block-search__text-button.alignleft {
+    float: none;
+}
+
+.wp-block-search__text-button.alignleft .wp-block-search__inside-wrapper {
+    margin:0 auto 0 0;
+}
\ No newline at end of file