You can use transitions instead:
.successfully-saved.hide-opacity{
opacity: 0;
}
.successfully-saved {
color: #FFFFFF;
text-align: center;
-webkit-transition: opacity 3s ease-in-out;
-moz-transition: opacity 3s ease-in-out;
-ms-transition: opacity 3s ease-in-out;
-o-transition: opacity 3s ease-in-out;
opacity: 1;
}