JSFiddle - React, Tailwind, and code Playground

HTML

<nav id="menu" class="dark_menu">
    <!-- Main Nav Start -->
    <ul id="main-nav" class="clearfix">
        <li id="port" class="parent menu-item"><a href="portfolio.html">Portfolio</a>

            <ul class="clearfix">
                <li id="regular" class="parent menu-item"><a href="#">Regular</a>

                    <ul class="clearfix">
                        <li id="menu-item-1036" class="menu-item"><a href="#">4 columns</a>

                        </li>
                        <li id="menu-item-1033" class="menu-item"><a href="#">3 columns</a>

                        </li>
                        <li id="menu-item-1030" class="menu-item"><a href="#">3 columns w/ sidebar</a>

                        </li>
                        <li id="menu-item-1029" class="menu-item"><a href="#">2 columns</a>

                        </li>
                    </ul>
                </li>
                <li id="2col" class="parent menu-item"><a href="#">Ajax</a>

                </li>
            </ul>
        </li>
        <li id="menu-item-1727" class="parent menu-item"><a href="">About</a>

            <ul class="clearfix">
                <li id="menu-item-870" class="menu-item"><a href="">Who We Are</a>

                </li>
                <li id="menu-item-872" class="menu-item"><a href="">What We Do</a>

                </li>
            </ul>
        </li>
    </ul>
</nav>

CSS

/* Main Navigation Menu */
 a {
    text-decoration:none;
}
ul {
    padding-left:0px;
}
#menu {
    position:relative;
    border:none;
    height:auto;
    top:34px;
    left:0px;
}
#menu ul {
    margin:0;
    list-style:none;
}
#menu li {
    float:left;
    position:relative;
}
#menu > ul > li > a {
    padding:25px 26px 17px;
    border-bottom:3px solid transparent;
    margin-right:1px;
    color:#6B6B6B;
    font:11px Arial, sans-serif;
    font-weight:bold;
    text-align:center;
    text-transform:uppercase;
    display:block;
}
#menu > ul > li:hover > a {
    color:#F15A2B;
    border-color:#F15A2B;
}
#menu > ul li.selected > a, #menu > ul li.selected:hover > a {
    color:#3B3B3B;
    border-color:#3B3B3B;
}
/* Submenu (second level) */
 #menu li > ul {
    position:absolute;
    top:auto;
    left:0;
    width:180px;
    max-height:0;
    box-shadow:1px 2px 10px rgba(100, 100, 100, 0.3);
    visibility: hidden;
    z-index:99999;
    overflow:hidden;
    -webkit-transition: max-height 0.2s ease, visibility 0s linear 0.5s;
    -moz-transition: max-height 0.2s ease, visibility 0s linear 0.5s;
    -o-transition: max-height 0.2s ease, visibility 0s linear 0.5s;
    -ms-transition: max-height 0.2s ease, visibility 0s linear 0.5s;
    transition: max-height 0.2s ease, visibility 0s linear 0.5s;
    background: inherit !important;
}
#menu ul li:hover > ul {
    visibility: visible;
    max-height: 216px;
    transition-delay: 0s;
}
#menu ul li > ul:hover {
    overflow:visible;
}
#menu li > ul li {
    height:36px;
    width:100%;
    border-bottom:1px solid #EEE;
    padding-top:0;
}
#menu li > ul li:last-child {
    border-bottom:none;
}
#menu li > ul li a {
    background:#FFF;
    padding:11px 15px;
    height:35px;
    color:#999;
    width:100%;
    font:10px Arial, sans-serif;
    font-weight:bold;
    text-align:left;
    text-transform:uppercase;
    display:block;
}
#menu li > ul li:hover > a {
    color:#FFF;
    background:#F15A2B;
}
#menu li >...