diff --git a/index.html b/index.html
index fc877d4..6058116 100644
--- a/index.html
+++ b/index.html
@@ -762,6 +762,7 @@
 
     </div>
   </footer>
+  <script src="https://cdnjs.cloudflare.com/ajax/libs/tether/1.3.1/js/tether.min.js"></script>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.0.0-alpha.6/js/bootstrap.min.js"></script>
   <script src="https://cdn.jsdelivr.net/jquery.scrollto/2.1.0/jquery.scrollTo.min.js"></script>