HTML часть. Не забываем подключить jquery.
<!DOCTYPE html>
<html lang="en">
<link rel="stylesheet" href="css/burger_menu.css">
<head>
<meta charset="UTF-8">
<title>Burger menu</title>
</head>
<body>
<div class="section">
<div class="menu-block">
<nav class="menu-nav">
<a class="menu-nav__link" href="#">Главная</a>
<a class="menu-nav__link" href="#">Портфолио</a>
<a class="menu-nav__link" href="#">Обо мне</a>
<a class="menu-nav__link" href="#">Контакты</a>
</nav>
<a href="#" class="menu-btn">
<span></span>
</a>
</div>
</div>
<script src="js/jquery-3.3.1.min.js"></script>
<script src="js/transform.js"></script>
</body>
</html>
CSS часть.
body{
margin: 0;
font-family: sans-serif;
}
.section{
background-color: #5c6bc0;
height: 100vh;
display: -webkit-flex;
display: -moz-flex;
display: -ms-flex;
display: -o-flex;
display: flex;
justify-content: center;
align-content: center;
align-items: center;
}
.menu-btn{
display: block;
width: 50px;
height: 50px;
border-radius: 50%;
background-color:#fff;
position: relative;
}
.menu-btn span,
.menu-btn span::before,
.menu-btn span::after{
position:absolute;
top:50%;
margin-top: -1px;
left: 50%;
margin-left: -10px;
width: 20px;
height: 2px;
background-color: #000;
}
.menu-btn span::before,
.menu-btn span::after{
content:'';
display: block;
-webkit-transition: 0.5s;
-o-transition: 0.5s;
transition: 0.5s;
}
.menu-btn span::before{
transform: translateY(-5px);
}
.menu-btn span::after{
transform: translateY(5px);
}
.menu-btn_active span:before {
transform: rotate(-35deg);
width: 10px;
transform-origin: left bottom;
}
.menu-btn_active span:after {
transform: rotate(35deg);
width: 10px;
transform-origin: left top;
}
.menu-block{
display: -webkit-flex;
display: -moz-flex;
display: -ms-flex;
display: -o-flex;
display: flex;
justify-content: center;
align-items: center;
}
.menu-nav{
background-color: #fff;
height: 50px;
line-height: 50px;
padding-left: 20px;
padding-right: 40px;
margin-right: -25px;
border-bottom-left-radius: 50px;
border-top-left-radius: 50px;
}
.menu-nav__link{
display:inline-block;
text-decoration: none;
color: #222;
margin-right: 20px;
}
.menu-nav{
transition: 0.4s;
transform-origin: right center; /*смещаеп трансформацию вправо */transform: scaleX(0) translateX(4.5%);
opacity: 0;
}
.menu-nav_active{
transform: scaleX(1) translateX(0%);
opacity: 1;
}
Немного jquery
$('.menu-btn').on('click', function(e) {
e.preventDefault();
$(this).toggleClass('menu-btn_active');
$('.menu').toggleClass('menu_active');
});
Пример
