[ADD] animation on hover

static/src/main.css

@@ -9,8 +9,24 @@
 	cursor: pointer;
 	-webkit-cursor: pointer;
 	-moz-cursor: pointer;
+	animation: 0.5s menu-bell 1;
 }
 
 .eiru_sidebar_toggler i {
 	color: #fff;
+}
+
+@keyframes menu-bell {
+    0% {
+        transform: rotate(30deg);
+    }
+    25% {
+        transform: rotate(-30deg);
+    }
+    50% {
+        transform: rotate(30deg);
+    }
+    75% {
+        transform: rotate(-30deg);
+    }
 }