Simple Mobile-Menu

HTML

<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css">
<body>
    <div id="side_menu">
        <ul>
            <li><a href="#">Home</a></li>
            <li><a href="#">Work</a></li>
            <li><a href="#">About</a></li>
            <li><a href="#">Contact</a></li>
        </ul>
    </div>
    
    <div id="wrapper">
        <div id="header">
            <a href="javascript:void(0)" id="show_side_menu"><i id="site_menu_icon" class="fa fa-bars"></i></a>
        </div>
        <div id="content">
            <h1>Welcome ...</h1>
            <p>... to my clean website.</p>
        </div>
    </div>
    
</body>

CSS

/* Simple Reset
-------------------------------------------------- */
html, body, * {
	box-sizing: border-box;
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	-oz-box-sizing: border-box;
	outline: none !important;
}

html, body {
	margin: 0;
	padding: 0;
	height: 100%;
	overflow-x: hidden;
}

html {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 16px;
	color: #868686;
	line-height: 24px;
}

/* Main 
-------------------------------------------------- */
a {
	color: #252425;
	text-decoration: none;
    -webkit-transition: color .2s linear;
    -moz-transition: color .2s linear;
    -o-transition: color .2s linear;
    -ms-transition: color .2s linear;
    transition: color .2s linear;
}

a:hover {
	color: #969696;
	text-decoration: none;
    -webkit-transition: color .2s linear;
    -moz-transition: color .2s linear;
    -o-transition: color .2s linear;
    -ms-transition: color .2s linear;
    transition: color .2s linear;
}

h1,h2,h3,h4,
h6,h7 {
	color: #252425;
	margin: 0 0 20px 0;
	text-transform: uppercase;
	line-height: 34px;
}

/* Wrapper
-------------------------------------------------- */
#wrapper {
	overflow-y: hidden;
	left: 0px;
	transition: left .2s ease-in-out;
	width: 100%;
	position: relative;
}

.push_wrapper_left {
	left: 250px !important;
	transition: left .2s ease-in-out;
}

/* Header
-------------------------------------------------- */
#header {
	padding: 40px 20px;
	width: 100%;
	color: #CCC; 
	background: #fff;
    border-bottom: 1px solid #e5e5e5;
}

#side_menu {
    border-right: 1px solid #e5e5e5;
    padding: 40px 0;
	position: fixed;
	left: 0;
	top: 0;
	height: 100%;
	width: 250px;
	left: -550px;
	background: #fff;
	overflow-x: hidden;
	overflow-y: auto;
	transition: left .2s ease-in-out;
}

#side_menu ul {
	list-style: none;
	margin: 0;
	padding: 0;
}
#side_menu ul li {}
#side_menu ul li a {
	display: block;
	padding: 10px 15px;
}

.push_side_menu_left {
	left: 0 !important;
	transition: left .2s...

JavaScript

$('#show_side_menu').on('click', function() {
	$('#side_menu').toggleClass('push_side_menu_left'); 
	$('#wrapper').toggleClass('push_wrapper_left'); 
	$('#site_menu_icon').toggleClass('fa-times')	
	$('#site_menu_icon').toggleClass('fa-bars');;
});