CSS only (no icon sets) Codepen
.nav-link #navBars {_x000D_
margin-top: -3px;_x000D_
padding: 8px 15px 3px;_x000D_
border: 1px solid rgba(0,0,0,.125);_x000D_
border-radius: .25rem;_x000D_
}_x000D_
_x000D_
.nav-link #navBars input {_x000D_
display: none;_x000D_
}_x000D_
_x000D_
.nav-link #navBars span {_x000D_
position: relative;_x000D_
z-index: 1;_x000D_
display: block;_x000D_
margin-bottom: 6px;_x000D_
width: 24px;_x000D_
height: 2px;_x000D_
background-color: rgba(125, 125, 126, 1);_x000D_
border-radius: .25rem;_x000D_
}
_x000D_
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<nav class="navbar navbar-expand-lg navbar-light bg-light">_x000D_
<!-- <a class="navbar-brand" href="#">_x000D_
<img src="https://getbootstrap.com/docs/4.0/assets/brand/bootstrap-solid.svg" width="30" height="30" class="d-inline-block align-top" alt="">_x000D_
Bootstrap_x000D_
</a> -->_x000D_
<!-- https://stackoverflow.com/questions/26317679 -->_x000D_
<a class="nav-link" href="#">_x000D_
<div id="navBars">_x000D_
<input type="checkbox" /><span></span>_x000D_
<span></span>_x000D_
<span></span>_x000D_
</div>_x000D_
</a>_x000D_
<!-- /26317679 -->_x000D_
<div class="collapse navbar-collapse" id="navbarNav">_x000D_
<ul class="navbar-nav">_x000D_
<li class="nav-item active"><a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a></li>_x000D_
<li class="nav-item"><a class="nav-link" href="#">Features</a></li>_x000D_
<li class="nav-item"><a class="nav-link" href="#">Pricing</a></li>_x000D_
<li class="nav-item"><a class="nav-link disabled" href="#">Disabled</a></li>_x000D_
</ul>_x000D_
</div>_x000D_
</nav>
_x000D_