diff --git a/custom.css b/custom.css
index 021465e..557f471 100644
--- a/custom.css
+++ b/custom.css
@@ -84,7 +84,7 @@
   animation-iteration-count: infinite;
 }
 
-.shake {
+@keyframes shake {
   0% { transform: translate(1px, 1px) rotate(0deg); }
   10% { transform: translate(-1px, -2px) rotate(-1deg); }
   20% { transform: translate(-3px, 0px) rotate(1deg); }