<div id='cssmenu'>
<ul>
   <li><a href='#'>Home</a></li>
   <li class='active has-sub'><a href='#'>Products</a>
      <ul>
         <li class='has-sub'><a href='#'>Product 1</a>
            <ul>
               <li><a href='#'>Sub Product</a></li>
               <li><a href='#'>Sub Product</a></li>
            </ul>
         </li>
         <li class='has-sub'><a href='#'>Product 2</a>
            <ul>
               <li><a href='#'>Sub Product</a></li>
               <li><a href='#'>Sub Product</a></li>
            </ul>
         </li>
      </ul>
   </li>
   <li><a href='#'>About</a></li>
   <li><a href='#'>Contact</a></li>
</ul>
</div>
@import url(https://fonts.googleapis.com/css?family=Raleway:400,200);
#cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
#cssmenu {
  width: 220px;
  font-family: Raleway, sans-serif;
  color: #ffffff;
}
#cssmenu ul ul {
  display: none;
}
#cssmenu > ul > li.active > ul {
  display: block;
}
.align-right {
  float: right;
}
#cssmenu > ul > li > a {
  padding: 16px 22px;
  cursor: pointer;
  z-index: 2;
  font-size: 16px;
  text-decoration: none;
  color: #ffffff;
  background: #3ab4a6;
  -webkit-transition: color .2s ease;
  -o-transition: color .2s ease;
  transition: color .2s ease;
}
#cssmenu > ul > li > a:hover {
  color: #d8f3f0;
}
#cssmenu ul > li.has-sub > a:after {
  position: absolute;
  right: 26px;
  top: 19px;
  z-index: 5;
  display: block;
  height: 10px;
  width: 2px;
  background: #ffffff;
  content: "";
  -webkit-transition: all 0.1s ease-out;
  -moz-transition: all 0.1s ease-out;
  -ms-transition: all 0.1s ease-out;
  -o-transition: all 0.1s ease-out;
  transition: all 0.1s ease-out;
}
#cssmenu ul > li.has-sub > a:before {
  position: absolute;
  right: 22px;
  top: 23px;
  display: block;
  width: 10px;
  height: 2px;
  background: #ffffff;
  content: "";
  -webkit-transition: all 0.1s ease-out;
  -moz-transition: all 0.1s ease-out;
  -ms-transition: all 0.1s ease-out;
  -o-transition: all 0.1s ease-out;
  transition: all 0.1s ease-out;
}
#cssmenu ul > li.has-sub.open > a:after,
#cssmenu ul > li.has-sub.open > a:before {
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}
#cssmenu ul ul li a {
  padding: 14px 22px;
  cursor: pointer;
  z-index: 2;
  font-size: 14px;
  text-decoration: none;
  color: #dddddd;
  background: #49505a;
  -webkit-transition: color .2s ease;
  -o-transition: color .2s ease;
  transition: color .2s ease;
}
#cssmenu ul ul ul li a {
  padding-left: 32px;
}
#cssmenu ul ul li a:hover {
  color: #ffffff;
}
#cssmenu ul ul > li.has-sub > a:after {
  top: 16px;
  right: 26px;
  background: #dddddd;
}
#cssmenu ul ul > li.has-sub > a:before {
  top: 20px;
  background: #dddddd;
}
/* FUENTE: http://cssmenumaker.com/menu/flat-accordion-menu */
(function($){
$(document).ready(function(){

$('#cssmenu li.active').addClass('open').children('ul').show();
	$('#cssmenu li.has-sub>a').on('click', function(){
		$(this).removeAttr('href');
		var element = $(this).parent('li');
		if (element.hasClass('open')) {
			element.removeClass('open');
			element.find('li').removeClass('open');
			element.find('ul').slideUp(200);
		}
		else {
			element.addClass('open');
			element.children('ul').slideDown(200);
			element.siblings('li').children('ul').slideUp(200);
			element.siblings('li').removeClass('open');
			element.siblings('li').find('li').removeClass('open');
			element.siblings('li').find('ul').slideUp(200);
		}
	});

});
})(jQuery);

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js