<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<div class="container">
<ul id="accordion" class="accordion">
<li>
<div class="link"><i class="fa fa-laptop"></i>Laptops<i class="fa fa-chevron-down"></i></div>
<ul class="submenu">
<li><a href="#">Dell Acron</a></li>
<li><a href="#">HP Envy</a></li>
<li><a href="#">Macbook Air</a></li>
</ul>
</li>
<li>
<div class="link"><i class="fa fa-tv"></i>Smart TV<i class="fa fa-chevron-down"></i></div>
<ul class="submenu">
<li><a href="#">Sony Bravia</a></li>
<li><a href="#">Samsung</a></li>
<li><a href="#">MI</a></li>
</ul>
</li>
<li>
<div class="link"><i class="fa fa-mobile"></i>Mobiles<i class="fa fa-chevron-down"></i></div>
<ul class="submenu">
<li><a href="#">Samsung S9</a></li>
<li><a href="#">Apple X</a></li>
<li><a href="#">Honor Play</a></li>
</ul>
</li>
<li>
<div class="link"><i class="fa fa-globe"></i>Search Engines<i class="fa fa-chevron-down"></i></div>
<ul class="submenu">
<li><a href="#">Google</a></li>
<li><a href="#">Bing</a></li>
<li><a href="#">Yahoo</a></li>