JSFiddle - React, Tailwind, and code Playground

HTML

<div id="main">
  <nav id="menu">
    <ul>
      <li><a href="#">Home</a></li>
      <li><a href="#">Services</a>
        <ul class="dropdown">
          <li><a href="#">Link One ></a>
            <ul class="dropdown">
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
            </ul>
          </li>
          <li><a href="#">Link One ></a>
            <ul class="dropdown">
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
            </ul>
          </li>
          <li><a href="#">Link One ></a>
            <ul class="dropdown">
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
            </ul>
          </li>
        </ul>
      </li>
      <li><a href="#">Projects</a>
        <ul class="dropdown">
          <li><a href="#"> Link One</a>
            <ul class="dropdown">
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
              <li><a href="#">Child Link One</a></li>
            </ul>
          </li>
          <li><a href="#"> Link One</a></li>
          <li><a href="#"> Link One</a></li>
        </ul>
      </li>
      <li><a href="#">Blog</a></li>
      <li><a href="#">Contact</a></li>
    </ul>
  </nav>
</div>

CSS

html {
  font-family: sans-serif;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

*:before,
*:after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

* {
  margin: 0px;
  padding: 0px;
}

#main {
  max-width: 1000px;
  margin: 0 auto;
}

#menu:after {
  content: "";
  clear: both;
  display: block;
}

#menu {
  background-color: #000;
}

#menu ul {
  list-style: none;
  position: relative;
  margin: 0;
  padding: 0
}

#menu ul a {
  display: block;
  font-size: 12px;
  text-decoration: none;
}

#menu ul li {
  margin: 0;
  padding: 0;
  display: block;
}


#menu .dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  z-index: 5;
}

#menu .dropdown li {
  width: 200px;
  display: block;
  background-color: gray;
  border-bottom: 1px solid black;
}

#menu .dropdown > li > a {
  font-style: 14px;
  padding: 5px;
  color: white;
  font-family: FFMarkStdBook;
}

#menu .dropdown .dropdown {
  top: 0;
  left: 100%;
  height: 100%;
}

#menu ul li:hover > .dropdown {
  display: block
}

#menu>ul>li {
  float: left;
  margin-right: 47px;
  position: relative;
}

#menu>ul>li:last-child {
  margin-right: 0px;
}

#menu>ul>li>a {
  color: #fff;
  text-transform: uppercase;
  font-size: 14px;
  padding: 10px;
  text-decoration: none;
}

#menu>ul>li>ul b {
  color: #4598cc;
  font-size: 14px;
  text-transform: uppercase;
  font-weight: normal;
}