Bootstrap Navbar Top fixe
<section id="headnev" class="navbar navbar-fixed-top">
Panicky Platypus
<section id="headnev" class="navbar navbar-fixed-top"> <nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">Navbar</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavAltMarkup" aria-controls="navbarNavAltMarkup" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarNavAltMarkup">
<div class="navbar-nav">
<a class="nav-item nav-link active" href="#">Home <span class="sr-only">(current)</span></a>
<a class="nav-item nav-link" href="#">Features</a>
<a class="nav-item nav-link" href="#">Pricing</a>
<a class="nav-item nav-link disabled" href="#">Disabled</a>
</div>
</div>
</nav><!-- Image and text -->
<nav class="navbar navbar-light bg-light">
<a class="navbar-brand" href="#">
<img src="/docs/4.0/assets/brand/bootstrap-solid.svg" width="30" height="30" class="d-inline-block align-top" alt="">
Bootstrap
</a>
</nav><nav class="navbar navbar-light bg-light">
<form class="form-inline">
<button class="btn btn-outline-success" type="button">Main button</button>
<button class="btn btn-sm btn-outline-secondary" type="button">Smaller button</button>
</form>
</nav>