<nav>
    <ul>
        <li><a href="https://facebook.com">Company</a></li>
        <li><a href="#">Services</a></li>
        <li><a href="#">Social</a></li>
        <li><a href="#">Contact</a></li>
    </ul>
</nav>
    
<div class="menu-btn">
    <a class="btn-open" href="javascript:void(0)"></a>
</div>

<div class="overlay">
    <div class="menu">
        <ul>


            <li><a href="#">About</a>
                <ul>
                    <li><a href="#">About Company</a></li>
                    <li><a href="#">Designers</a></li>
                    <li><a href="#">Developers</a></li>
                </ul>
            </li>

            <li><a href="#">Services</a>
                <ul>
                    <li><a href="#">Web design</a></li>
                    <li><a href="#">Development</a></li>
                    <li><a href="#">Apps</a></li>
                    <li><a href="#">Graphic Design</a></li>
                    <li><a href="#">Seo</a></li>
                </ul>
            </li>

            <li><a href="#">Work</a>
                <ul>
                    <li><a href="#">Web</a></li>
                    <li><a href="#">Graphics</a></li>
                    <li><a href="#">Apps</a></li>
                    <li><a href="#">Seo</a></li>
                </ul>
            </li>

            <li><a href="#">Social</a>
                <ul>
                    <li><a href="#">Facebook</a></li>
                    <li><a href="#">Twitter</a></li>
                    <li><a href="#">Codepen</a></li>
                    <li><a href="#">Behance</a></li>
                    <li><a href="#">Dribbble</a></li>
                </ul>
            </li>


        </ul>
    </div>
</div>

<h4>Example #2 - Full menu with second menu</h4>

<!-- Github button -->

<a  href="https://github.com/marioloncarek/responsive-overlay-menu" target="_blank"><img style="position: absolute; top: 0; left: 0; border: 0;" src="https://camo.githubusercontent.com/567c3a48d796e2fc06ea80409cc9dd82bf714434/68747470733a2f2f73332e616d617a6f6e6177732e636f6d2f6769746875622f726962626f6e732f666f726b6d655f6c6566745f6461726b626c75655f3132313632312e706e67"
  alt="Fork me on GitHub" data-canonical-src="https://s3.amazonaws.com/github/ribbons/forkme_left_darkblue_121621.png"></a>

<a href="https://codepen.io/collection/ANqMpL/" target="_blank"><div class="allexamples">View all examples</div></a>

/* 
- Name: Responsive overlay menu framework
- Version: 1.0
- Latest update: 15.9.2015.
- Author: Mario Loncarek
- Author web site: http://marioloncarek.com
*/

body,
html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    font-family: 'Raleway', sans-serif;
}

h3 {
    color: #e9e9e9;
    text-align: center;
    margin: 0;
    padding: 10px 0 0;
}

h4 {
    color: #333;
    text-align: center;
    margin: 0;
    padding: 10px 0 0;
}

a {
    text-decoration: none;
    -webkit-transition: all .3s ease;
    -moz-transition: all .3s ease;
    -ms-transition: all .3s ease;
    -o-transition: all .3s ease;
    transition: all .3s ease;
}
/* OUTER NAV */
nav {
    position: relative;
    overflow: hidden;
    width: 100%;
    height: auto;
    background: none;
    text-align: center;
}
nav ul {
    text-align: center;
}
nav ul li {
    display: inline-block;
}
nav ul li a {
    display: inline-block;
    padding: 1em 3em;
    border-bottom: 2px solid #fff;
    color: #333;
    text-decoration: none;
    font-size: 16px;
    -webkit-transition: all .2s linear 0s;
    -moz-transition: all .2s linear 0s;
    -o-transition: all .2s linear 0s;
    transition-property: all .2s linear 0s;
}
nav ul li a:hover {
    color: #34B484;
}
/* OPEN / CLOSE BTNS */
.menu-btn {
    position: absolute;
    top: 6px;
    right: 20px;
    z-index: 999;
    display: inline;
    font-size: 32px;
}
.menu-btn a {
    display: inline-block;
    text-decoration: none;
    /* safari hack */
}
.btn-open:after {
    color: #333;
    content: "\f394";
    font-family: "Ionicons";
    -webkit-transition: all .2s linear 0s;
    -moz-transition: all .2s linear 0s;
    -o-transition: all .2s linear 0s;
    transition-property: all .2s linear 0s;
}
.btn-open:hover:after {
    color: #34B484;
}
.btn-close:after {
    color: #fff;
    content: "\f2d7";
    font-family: "Ionicons";
    -webkit-transition: all .2s linear 0s;
    -moz-transition: all .2s linear 0s;
    -o-transition: all .2s linear 0s;
    transition-property: all .2s linear 0s;
}
.btn-close:hover:after {
    color: #34B484;
}
/* OVERLAY */
.overlay {
    position: fixed;
    top: 0;
    z-index: 99;
    display: none;
    overflow: auto;
    width: 100%;
    height: 100%;
    background: #333;
}
.overlay .menu {
    margin: 10% auto;
    width: 80%;
}
.overlay .menu ul {
    margin: 0;
    padding: 0;
    width: 100%;
}
.overlay .menu ul li {
    float: left;
    padding: 20px 0;
    width: 25%;
    list-style: none;
    text-align: center;
    text-transform: uppercase;
}
.overlay .menu ul li a {
    color: #34B484;
    font-weight: bold;
    font-size: 20px;
}
.overlay .menu ul ul {
    margin-top: 50px;
}
.overlay .menu ul ul li {
    position: relative;
    float: none;
    margin: 0;
    width: 100%;
    border: 0;
}
.overlay .menu ul ul li a {
    color: #fff;
    text-transform: capitalize;
    font-weight: bold;
    font-size: 14px;
}
.overlay .menu ul ul li a:hover {
    color: #34b484;
}
/* RESPONSIVE */
@media screen and (max-width: 768px) {
    nav {
        display: none;
    }
    .overlay .menu ul li {
        float: none;
        margin-bottom: 50px;
        width: 100%;
        border-bottom: 1px solid #575757;
    }
    .overlay .menu ul li:last-child {
        border: 0;
    }
    .overlay .menu ul ul {
        margin-top: 20px;
    }
    .menu-btn {
        right: 25px;
    }
}

.allexamples{
  position:absolute;
  bottom:0;
  font-size:18px;
  font-weight:bold;
  width:100%;
  text-align:center;
  background:#e9e9e9;
  padding:20px;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  color:#333;
  position:fixed;
} 

$(document).ready(function () {

    $(".menu-btn a").click(function () {
        $(".overlay").fadeToggle(200);
        $(this).toggleClass('btn-open').toggleClass('btn-close');
    });

    $('.overlay').on('click', function () {
        $(".overlay").fadeToggle(200);
        $(".menu-btn a").toggleClass('btn-open').toggleClass('btn-close');
    });

    $('.menu a').on('click', function () {
        $(".overlay").fadeToggle(200);
        $(".menu-btn a").toggleClass('btn-open').toggleClass('btn-close');
    });

});