JSFiddle - React, Tailwind, and code Playground

HTML

<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">

<!-- Optional theme -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap-theme.min.css" integrity="sha384-rHyoN1iRsVXV4nD0JutlnGaslCJuC7uwjduW9SVrLvRYooPp2bWYgmgJQIXwl/Sp" crossorigin="anonymous">

<!-- Latest compiled and minified JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<header>     
    <div class="navbar navbar-default navbar-fixed-top bg-red" role="navigation">
        <div class="container">
            <div class="navbar-header">
                <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
                    <span class="sr-only">Toggle navigation</span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>
                <h1 class="text-white">MeuSite</h1>
            </div>
            @Html.Partial("_LoginForm")
        </div>
    </div>
</header>
<div class="div_loading"></div>

CSS

.div_loading  {    
    position:absolute;
    top:0;
    left:0;
    z-index:2;
    background-color:#000;
    width:100%;
    min-height:100%;
    height:auto;
    opacity: .50;
    filter: alpha(opacity=65);
}
.navbar, .navbar-fixed-top, .navbar-defeault {
z-index:1!important;
}