<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<header class="header">
<nav class="navbar navbar-toggleable-md navbar-light pt-0 pb-0 ">
<button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<a class="navbar-brand p-0 mr-5" href="#"><img src="http://via.placeholder.com/61x14"></a>
<div class="float-left"> <a href="#" class="button-left"><span class="fa fa-fw fa-bars "></span></a> </div>
<div class="collapse navbar-collapse flex-row-reverse" id="navbarNavDropdown">
<ul class="navbar-nav">
<li class="nav-item dropdown messages-menu">
<a class="nav-link dropdown-toggle" href="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<i class="fa fa-bell-o"></i>
<span class="label label-success bg-success">10</span>
</a>
<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
<ul class="dropdown-menu-over list-unstyled">
<li class="header-ul text-center">You have 4 messages</li>
<li>
<ul class="menu list-unstyled">
<li>
<a href="#">
<div class="pull-left">
<img src="http://via.placeholder.com/160x160" class="rounded-circle " alt="User Image">
</div>
<h4>
Support Team
<small><i class="fa fa-clock-o"></i> 5 mins</small>