change the default color of .active tab bootstrap
Bootstrap does something really silly to me and puts just about all of the actual styling on the <a> tag in the navigation, instead of the <li> like most people would do. You should change most styles on .active a instead of just .active
.active a {
background-color: green !important;
}<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" />
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#main_navbar">
<span class="fa fa-bars"></span>
</button>
<a class="navbar-brand" href="#">Navbar</a>
</div>
<div class="collapse navbar-collapse" id="main_navbar">
<ul class="nav navbar-nav">
<li class="active"><a href="#">Menu 1</a>
</li>
<li><a href="#">Menu 2</a>
</li>
<li><a href="#">Menu 3</a>
</li>
</ul>
</div>
</div>
</nav>