<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>
<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Document</title>
<link rel="stylesheet" href="bootstrap-3.3.7-dist/css/bootstrap.css">
<link rel="stylesheet" href="style.css">
</head>
<body>
<div id="big_container" class="col-md-12">
<div id="small_container" class="col-md-6">
<h1 id="ww">Welcome</h1>
<div id="input_container" class="col-md-12">
<div class="input-group">
<span class="input-group-addon" id="basic-addon1"><span class="glyphicon glyphicon-user"></span></span>
<input type="text" class="form-control" placeholder="Username" aria-describedby="basic-addon1">
</div>
<div class="input-group">
<span class="input-group-addon" id="basic-addon1"><span class="glyphicon glyphicon-lock"></span></span>
<input type="password" class="form-control" placeholder="Password" aria-describedby="basic-addon1">
</div>
<p><a id="btn" class="btn btn-primary btn-lg" href="#" role="button">LOGIN</a></p>
</div>