JSFiddle - React, Tailwind, and code Playground

HTML

<nav class="nav-menu">
    <ul>
        <li><a href="#">Option 1</a></li>
        <li>
            <a href="#">Option 2</a>
            <ul>
                <li><a href="#">Sub Option</a></li>
            </ul>
        </li>
        <li>
            <a href="#">Option 3</a>
            <ul>
                <li><a href="#">Sub Option</a></li>
            </ul>
        </li>
        <li>
            <a href="#">Option 4</a>
            <ul>
                <li><a href="#">Sub Option</a></li>
            </ul>
        </li>
    </ul>
</nav>

CSS

.nav-menu {
   background-color:#FEFFE5;  
   clear:both;
   float:left;
   margin:0px 0px 15px 0px;
   border-bottom: 1px solid #dbd7d4;
   width:100%;
   font-size:13px;  
   z-index:1000; /* This makes the dropdown menus appear above the page content below */
   position:relative;
}

/* Top menu items */
.nav-menu ul {
   margin:0;
   padding:0;
   list-style:none;
   float:right;
   position:relative;
   right:50%;
}
.nav-menu ul li {
   margin:0 0 0 1px;
   padding:0;
   float:left;
   position:relative;
   left:50%;
   top:1px;
}
.nav-menu ul li a {
   display:block;
   margin:0;
   text-decoration:none;
   color:Black;
   padding-left: 12px;
   padding-right: 12px;
   line-height: 38px;
}
.nav-menu ul li a:hover {
   color:#FFFFFF;
   background-color:Red;
}
.nav-menu ul li:hover a,
.nav-menu ul li.hover a { /* This line is required for IE 6 and below */
   color:#FFFFFF;
   background-color:Red;
}

/* Submenu items */
.nav-menu ul ul {
   display:none; /* Sub menus are hiden by default */
   position:absolute;
   top:36px;
   left:0;
   right:auto; /*resets the right:50% on the parent ul */
   background: #F8F8F8;
   width: 250px;
   z-index: 1000;
}
.nav-menu ul ul li {
   left:auto;  /*resets the left:50% on the parent li */
   margin:0; /* Reset the 1px margin from the top menu */
   clear:left;
   width:100%;
   border: 1px solid #AEAEAE;
   border-top: 0;
}
.nav-menu ul ul li a,
.nav-menu ul li.active li a,
.nav-menu ul li:hover ul li a,
.nav-menu ul li.hover ul li a { /* This line is required for IE 6 and below */
   font-weight:normal; /* resets the bold set for the top level menu items */
   color:Black;
   line-height:28px; /* overwrite line-height value from top menu */
   background: none;
}
.nav-menu ul ul li a:hover,
.nav-menu ul li.active ul li a:hover,
.nav-menu ul li:hover ul li a:hover,
.nav-menu ul li.hover ul li a:hover { /* This line is required for IE 6 and below */
    background: #ccc;
    background: rgba(204,204,204,0.5);
}

/*...