diff --git a/spectrum.css b/spectrum.css
index a8ad9e4f..1d4e1d19 100644
--- a/spectrum.css
+++ b/spectrum.css
@@ -417,7 +417,7 @@ See http://bgrins.github.io/spectrum/themes/ for instructions.
 }
 
 
-/* Buttons: http://hellohappy.org/css3-buttons/ */
+/* Buttons: https://ubuwaits.github.io/css3-buttons/ */
 .sp-container button {
   background-color: #eeeeee;
   background-image: -webkit-linear-gradient(top, #eeeeee, #cccccc);