JSFiddle - React, Tailwind, and code Playground

HTML

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<div id="dd" class="select-wrapper">--- Select ---
<div class="categories">
 <div class="category">1</div>
 <div class="category">2</div>
 <div class="category">3</div>
</div>
</div>

CSS

.select-wrapper {
    /* Size & position */
    position: relative;
    width: 200px;
    margin-top: 25px;
    margin-left: 25px;
    padding: 12px 15px;

    /* Styles */
    background: #fff;
    border-radius: 5px;
    box-shadow: 0 1px 0 rgba(0,0,0,0.2);
    cursor: pointer;
    outline: none;
    -webkit-transition: all 0.3s ease-out;
    -moz-transition: all 0.3s ease-out;
    -ms-transition: all 0.3s ease-out;
    -o-transition: all 0.3s ease-out;
    transition: all 0.3s ease-out;
}

.select-wrapper:after { /* Little arrow */
    content: "";
    width: 0;
    height: 0;
    position: absolute;
    top: 50%;
    right: 15px;
    margin-top: -3px;
    border-width: 6px 6px 0 6px;
    border-style: solid;
    border-color: #4cbeff transparent;
}

.select-wrapper .categories {
    /* Size & position */
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;

    /* Styles */
    background: #fff;
    border-radius: 0 0 5px 5px;
    border: 1px solid rgba(0,0,0,0.2);
    border-top: none;
    border-bottom: none;
    list-style: none;
    -webkit-transition: all 0.3s ease-out;
    -moz-transition: all 0.3s ease-out;
    -ms-transition: all 0.3s ease-out;
    -o-transition: all 0.3s ease-out;
    transition: all 0.3s ease-out;

    /* Hiding */
    max-height: 0;
    overflow: hidden;
}


.select-wrapper .categories div {
    display: block;
    text-decoration: none;
    color: #333;
    padding: 10px;
    transition: all 0.3s ease-out;
    border-bottom: 1px solid #e6e8ea;
}


/* Hover state */

.select-wrapper .categories div:hover {
    color: #57a9d9;
}

/* Active state */

.select-wrapper.active {
    border-radius: 5px 5px 0 0;
    background: #4cbeff;
    box-shadow: none;
    border-bottom: none;
    color: white;
}

.select-wrapper.active:after {
    border-color: #82d1ff transparent;
}

.select-wrapper.active .categories {
    border-bottom: 1px solid rgba(0,0,0,0.2);
    max-height: 400px;
}

.select-wrapper:focus {
    border-radius:...

JavaScript

function DropDown(el) {
				this.dd = el;
				this.initEvents();
			}
			DropDown.prototype = {
				initEvents : function() {
					var obj = this;

					obj.dd.on('click', function(event){
						$(this).toggleClass('active');
						event.stopPropagation();
					});	
				}
			}

			$(function() {

				var dd = new DropDown( $('#dd') );

				$(document).click(function() {
					// all dropdowns
					$('.select-wrapper').removeClass('active');
				});

			});