dupre,
<!DOCTYPE html>
<html>
<head>
<style>
body {
font-family: "Lato", sans-serif;
position: relative;
}
.sidenav {
height: 100%;
width: 0;
position: fixed;
z-index: 1;
top: 0;
left: 0;
background-color: #111;
overflow-x: hidden;
transition: 0.5s;
padding-top: 60px;
}
.sidenav a {
padding: 8px 8px 8px 32px;
text-decoration: none;
font-size: 25px;
color: #818181;
display: block;
transition: 0.3s;
}
.sidenav a:hover, .offcanvas a:focus{
color: #f1f1f1;
}
.sidenav .closebtn {
position: absolute;
top: 0;
right: 25px;
font-size: 36px;
margin-left: 50px;
}
#main {
position: absolute;
left: 0px;
transition: left .5s;
padding: 16px;
}
@media screen and (max-height: 450px) {
.sidenav {padding-top: 15px;}
.sidenav a {font-size: 18px;}
}
.sidenav.open {
width: 250px
}
.sidenav.open ~ #main{
left:250px;
}
.openclosebtn{
font-size:30px;cursor:pointer
}
</style>
</head>
<body>
<div id="mySidenav" class="sidenav">
<a href="#">About</a>
<a href="#">Services</a>
<a href="#">Clients</a>
<a href="#">Contact</a>
</div>
<div id="main">
<h2>Sidenav Push Example</h2>
<p>Click on the element below to open the side navigation menu, and push this content to the right.</p>
<span class="openclosebtn">☰ open</span>
</div>
<script>
window.addEventListener('DOMContentLoaded', function() {
var sidenav = document.querySelector('.sidenav');
var openclosebtn = document.querySelector('.openclosebtn');
openclosebtn.addEventListener("click", function(event){
sidenav.classList.toggle("open")})
});
</script>
</body>
</html>