JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<div class="container-fluid">
  <div class="menu-container">
       <ul class="menu" id="sidemenu">
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
      <li><i class="fa fa-calendar-plus-o"></i><br />Dashboard</a></li>
    </ul>
  </div>

  <div class="content-container">
    <div class="header">
      <div class="row">
        <div class="col-sm-6">
          left header
        </div>
        <div class="col-sm-6 text-right">
          right header
        </div>
      </div>
    </div>
    <div class="page-content">
      <div class="row">
        <div class="col-sm-12">
          this is a row #1
        </div>
      </div>
      <div class="row">
        <div class="col-sm-12">
          this is a row #2
        </div>
      </div>
    </div>
  </div>
</div>

CSS

.menu-container {
  width: 120px;
  float: left;
  display: block;
  padding: 15px;
  padding-bottom: 0px;
  margin-bottom: 0px;
}

.content-container {
  width: 100%;
  padding-left: 120px;
}

.content-container .header {
  padding: 15px 20px;
  height: 60px;
}

.content-container .page-content {
  padding: 50px;
}