.navbar-light
<nav class="navbar navbar-expand-lg navbar-light bg-white" role="navigation">
<div class="container">
<a class="navbar-brand" href="#">Logo</a>
<button class="navbar-toggler" data-toggle="collapse" data-target="#navbar-collapse-1">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse justify-content-end" id="navbar-collapse-1">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#">Nav link</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Nav link</a>
</li>
<li class="nav-item dropdown dropdown-hover">
<a href="#" class="nav-link dropdown-toggle" data-toggle="dropdown">
Dropdown
</a>
<div class="dropdown-menu" role="menu">
<a class="dropdown-item" href="#">Item 1</a>
<a class="dropdown-item" href="#">Item 2</a>
<a class="dropdown-item" href="#">Item 3</a>
</div>
</li>
<li class="nav-item ml-lg-2 mt-2 mt-lg-0">
<a class="btn btn-pastel-primary ml-2" href="#">Buy now</a>
</li>
</ul>
</div>
</div>
</nav>
.navbar-dark
<nav class="navbar navbar-expand-lg navbar-dark bg-dark" role="navigation">
<div class="container">
<a class="navbar-brand" href="#">Logo</a>
<button class="navbar-toggler" data-toggle="collapse" data-target="#navbar-collapse-2">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbar-collapse-2">
<ul class="navbar-nav ml-auto">
... omitted for brevity ...
</ul>
<a class="btn btn-sky ml-auto mt-2 mt-lg-0" href="#">Buy now</a>
</div>
</div>
</nav>
<nav class="navbar navbar-expand-lg navbar-dark bg-transparent position-absolute w-100" role="navigation">
<div class="container">
<a class="navbar-brand" href="#">Logo</a>
<button class="navbar-toggler" data-toggle="collapse" data-target="#navbar-collapse-3">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse justify-content-end" id="navbar-collapse-3">
<ul class="navbar-nav">
... omitted for brevity ...
<li class="nav-item ml-2">
<form>
<input type="text" name="search" class="form-control" placeholder="Search...">
</form>
</li>
</ul>
</div>
</div>
</nav>
<nav class="navbar navbar-expand-lg navbar-light bg-transparent position-absolute w-100" role="navigation">
<div class="container">
<a class="navbar-brand" href="#">Logo</a>
<button class="navbar-toggler" data-toggle="collapse" data-target="#navbar-collapse-4">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse justify-content-end" id="navbar-collapse-4">
<ul class="navbar-nav ml-auto">
... omitted for brevity ...
</ul>
<form class="ml-auto">
<input type="text" name="search" class="form-control" placeholder="Search...">
</form>
</div>
</div>
</nav>