<head>
<link href="https://fonts.googleapis.com/css?family=Playfair+Display|Raleway" rel="stylesheet">
<script src="https://code.jquery.com/jquery-3.2.0.min.js"></script>
</head>
<body>
  <header> 
    <div class="hamburger-menu">
        <div class="bar"></div>	
    </div>
    
    <nav class="mobile-menu">
        <ul>
          <li><a href="index.html">Home</a></li>
          <li class="has-children">About <span class="icon-arrow"></span>
            <ul class="children">
              <li><a href="submenu1.html">Submenu #1</a></li>
              <li><a href="submenu2.html">Submenu #2</a></li>
              <li><a href="submenu3.html">Submenu #3</a></li>
            </ul>
          </li>
          <li><a href="blog.html">Blog</a></li>
          <li><a href="contact.html">Contact</a></li>				
        </ul>    
    </nav>
  </header>

  <div class="main">
    <div class="text">
      <h1>Mobile Menu with Hamburger</h1>
      <p>This is a mobile navigation menu with slide-in effect, hover effects and rotating arrow element for submenus.</p>
    </div>
  </div>
</body>
body {
  font-family: 'Raleway', sans-serif;
  font-size: 18pt;
}

h1 {
  font-family: 'Playfair Display', serif;
  font-size: 30pt;
}

.main {
  position: relative;
  width: 100%;
  max-width: 1000px;
  margin: 0 auto;
}

.text {
  position:absolute;
  text-align: center;
  top: 30px;
}

/*---------------------
HAMBURGER MENU
----------------------*/

.hamburger-menu {
  position: fixed;
  top: 0;
  left: 0;
  padding-top: 20px;
  padding-left: 15px;
  width: 100%;
  height: 43px;
  cursor: pointer;
  z-index: 9998;
  background:#EBEBEB;
  -webkit-tap-highlight-color: rgba(255, 255, 255, 0);
}

.bar,
.bar:after,
.bar:before {
  width: 30px;
  height: 3px;
}

.bar {
  position: relative;
  transform: translateY(10px);
  background: black;
  transition: all 0ms 300ms;
}

.bar.animate {
  background: rgba(255, 255, 255, 0);
}

.bar:before {
  content: "";
  position: absolute;
  left: 0;
  bottom: 10px;
  background: black;
  transition: bottom 300ms 300ms cubic-bezier(0.23, 1, 0.32, 1), transform 300ms cubic-bezier(0.23, 1, 0.32, 1);
}

.bar:after {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  background: black;
  transition: top 300ms 300ms cubic-bezier(0.23, 1, 0.32, 1), transform 300ms cubic-bezier(0.23, 1, 0.32, 1);
}

.bar.animate:after {
  top: 0;
  transform: rotate(45deg);
  transition: top 300ms cubic-bezier(0.23, 1, 0.32, 1), transform 300ms 300ms cubic-bezier(0.23, 1, 0.32, 1);
}

.bar.animate:before {
  bottom: 0;
  transform: rotate(-45deg);
  transition: bottom 300ms cubic-bezier(0.23, 1, 0.32, 1), transform 300ms 300ms cubic-bezier(0.23, 1, 0.32, 1);
}

/*---------------------
Mobiles Menu 
----------------------*/
	/*---------------------
	Mobiles Menu - Design 
	----------------------*/

.mobile-menu ul {
  margin: 0;
  padding: 0;
}

.mobile-menu li {
  font-size: 20px;
  line-height: 30px;
  margin: 0;
  overflow: hidden;
  padding: 5px;
  position: relative;
  text-align: left;
  text-transform: uppercase;
  padding-left:15px;
}

.mobile-menu li:first-child {
  margin-top: 70px;
}

.mobile-menu li:hover {
  background: #CCCCCC;
}

.mobile-menu li a {
  text-decoration: none;
  color: black;
}

	/*---------------------
	Mobiles Menu - Slide IN 
	----------------------*/

.mobile-menu {
  top: 0;
  max-width: 250px;
  left: -100%;
  width: 100%;
  background: #EBEBEB;
  color: black;
  height: 100%;
  position: fixed;
  z-index: 9997;
  overflow-y: auto;
  -webkit-transform: translate3d(0, 0, 205px);
  -moz-transform: translate3d(0, 0, 205px);
  transform: translate3d(0, 0, 205px);
  -webkit-transition: all 500ms ease-in-out;
  -moz-transition: all 500ms ease-in-out;
  transition: all 500ms ease-in-out;
}

.mobile-menu.active {
  left: 0;
  -webkit-transform: translate3d(0, 0, 0);
  -moz-transform: translate3d(0, 0, 0);
  transform: translate3d(0, 0, 0);
  -webkit-transition: all 500ms ease-in-out;
  -moz-transition: all 500ms ease-in-out;
  transition: all 500ms ease-in-out;
}

	/*---------------------
	Mobiles Menu - Dropdown Submenu
	----------------------*/

.has-children:hover{
	cursor:hand;
}

.children {
	display:none;	
}

.mobile-menu .children li:first-child {
  margin-top: 0px;
}

.icon-arrow {
	position: absolute;
	display: block;
	font-size: 0.7em;
	color: black;
	top: 5px;
	right: 10px;
  transform: rotate(0deg);
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg); 
	transition: .6s;
  -webkit-transition: .6s;
  -moz-transition: .6s;	 
}
  
.icon-arrow:after {
    content: "\25BC";
}

.icon-arrow.open {
  transform: rotate(-180deg);
  -webkit-transform: rotate(-180deg);
  -moz-transform: rotate(-180deg); 
  transition: .6s;
  -webkit-transition: .6s;
  -moz-transition: .6s; 		
}
View Compiled
(function () {
	$('.hamburger-menu').on('click', function() {
		$('.bar').toggleClass('animate');
    $('.mobile-menu').toggleClass('active');
    return false;
	})
  $('.has-children').on ('click', function() {
		   $(this).children('ul').slideToggle('slow', 'swing');
       $('.icon-arrow').toggleClass('open');
	});
})();
Run Pen

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

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