hamburger menu css
W/O JavaScript function()
/* You can use the :focus-within selector like this: */
/* HTML */
<div class="menu-container">
<button type="button" class="hamburger">Menu</button>
<nav class="navbar">...</nav>
</div>
/* CSS */
.menu-container .navbar {
display: none;
}
.menu-container:focus-within .navbar {
display: block;
}