JSFiddle - React, Tailwind, and code Playground

HTML

<body>
<div style="float: right">
        <button type="button" value="Decline" class="btn btn-danger" data-toggle="modal" data-target="#declineModal">Decline</button>
    </div>

    <!-- Modal -->
    <div class="modal fade" id="declineModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span></button>
                    <h4 class="modal-title" id="myModalLabel">Comment</h4>
                    </div>
                    <div class="modal-body">
                        <textarea class="form-control col-xs-12"></textarea>
                    </div>
                    <div class="modal-footer">
                    <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                    <button type="button" class="btn btn-danger">Decline</button>
                </div>
            </div>
        </div>
    </div> 
</body>

CSS

.form-control {
    width: 100%;
}