JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://www.bitstorm.org/jquery/color-animation/jquery.animate-colors.js"></script>
<button  class="reject">Reject</button>

CSS

.reject{padding:10px;font-size:20px;background:#F00;}

JavaScript

$(".reject").hover(function() {  
        $(this).animate({backgroundColor: '#000000'}, 1000);
    }, function(){  
        $(this).animate({backgroundColor: '#333333'}, 1000);  
    });