JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css">
<div class="submit">
    <i class="fa fa-plus" title="New Post" id="test"></i>
</div>

CSS

.fa-plus {
    cursor: pointer;
    font-size: 24px;
    color: #69f;
    transition: 0.25s;
}
.fa-red{
    color: #f00;
    transform : rotate(45deg);
}

JavaScript

$(".fa-plus").click(function () {
    $(this).toggleClass("fa-red");
});