<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<section class="login-container">
<div class="container">
<div class="row">
<div class="col-xs-12 col-sm-6 col-sm-offset-3 col-md-4 col-md-offset-4">
<div class="row">
<a href="#sign-in" class="btn btn-link active">Sign in</a>
<a href="#sign-up" class="btn btn-link">Sign up</a>
</div>
</div>
</div>
</div>
</section>
html, body { height: 100%; min-height: 1000px; width: 100%; }
.login-container {
background: transparent url(https://download.unsplash.com/photo-1428953773181-b4cf23cd7195) center center;
background-size: cover;
height: 100%;
padding-top: 60px;
width: 100%;
}
.login-container::before {
background: -webkit-radial-gradient(center, ellipse cover, rgba(43,44,78,0.9) 0%,rgba(43,44,78,0.9) 1%,rgba(43,44,78,1) 74%,rgba(43,44,78,1) 75%,rgba(43,44,78,1) 100%);
content: "";
height: 100%;
left: 0px;
position: absolute;
top: 0px;
width: 100%;
}
.login-container a.btn.btn-link {
color: rgb(255, 255, 255);
font-size: 180%;
margin: 0px 27px;
padding: 6px 0px;
opacity: 0.7;
text-transform: uppercase;
}
.login-container a.btn.btn-link.active {
border-bottom: 2px solid rgb(23, 98, 238);
opacity: 1;
}