Your nav menu bar responcive while can user bootstrap framework.
This like code insert in function.php
Bootstrap responcive nav menu wordpress
// This code insert in header.php
<div class="container">
<nav class="navbar navbar-default" role="navigation">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#medi-temp-navbar-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div class="collapse navbar-collapse" id="medi-temp-navbar-collapse">
<?php
if ( has_nav_menu( 'primary' ) ) {
wp_nav_menu( array(
'theme_location' => 'primary',
'container'=>false,
'walker'=>new wp_bootstrap_navwalker(),
'menu_class'=>'nav navbar-nav',
)
);
}
?>
</div>
</nav><!-- nav -->
</div><!-- container -->