CSS transition: fade background color, resetting after

$('input[type=button]').click( function() {
 $('#newContent').addClass('backgroundAnimated');
});

@-o-keyframes fadeIt {
  0%   { background-color: #FFFFFF; }
  50%  { background-color: #AD301B; }
  100% { background-color: #FFFFFF; }
}
@keyframes fadeIt {
  0%   { background-color: #FFFFFF; }
  50%  { background-color: #AD301B; }
  100% { background-color: #FFFFFF; }
}

.backgroundAnimated{    
    background-image:none !important; 
         -o-animation: fadeIt 5s ease-in-out; 
            animation: fadeIt 5s ease-in-out; 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>Old stuff</div>
<div>Old stuff</div>
<div>Old stuff</div>
<div id="newContent">New stuff, just added</div>

<input type="button" value="test" />