change all anchor alert closes to buttons

less/close.less

@@ -16,3 +16,14 @@
     cursor: pointer;
   }
 }
+
+// Additional properties for button version
+// iOS requires the button element instead of an anchor tag.
+// If you want the anchor version, it requires `href="#"`.
+button.close {
+  padding: 0;
+  cursor: pointer;
+  background-color: transparent;
+  border: 0;
+  -webkit-appearance: none;
+}