Salve, sto cercando di realizzare un template Html/CSS con Bootstrap ma ci sono problemi in quanto non riesco a nascondere il "button" ed inoltre il menù a tendina non appare cliccando "Droptown". Il sorgente è questo:

codice HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">    
<meta name="viewport" content="width=device-width, initial-scale=1">    <!-- The above 3 meta tags *must* come first in the head; any other head content must come *after* these tags -->    <title>Bootstrap 101 Template</title>        
<!-- Bootstrap -->    
<link href="css/bootstrap.min.css" rel="stylesheet">    <link href="css/custom.css"></link>    <!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->    <!-- WARNING: Respond.js doesn't work if you view the page via  -->    <!--[if lt IE 9]>      <script src="https://oss.maxcdn.com/html5shiv/3.7.3/html5shiv.min.js"></script>      <script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>    <![endif]-->  </head>  <body>    <div class="navbar navbar-inverse navbar-fixed-top" role="navigation">       <div class="container">           <div class="navbar-header">             <button type="button" class="navbar-toogle" data-toogle="collapse" data-target=".navbar-collapse">                 <span class="sr-only">Toogle navigation</span>                 <span class="icon-bar"></span>                 <span class="icon-bar"></span>                 <span class="icon-bar"></span>             </button>             <a class="navbar-brand" href="#">Bootstrap theme</a>           </div>           <div class="navbar-collapse collapse">             <ul class="nav navbar-nav">                <li class="active"><a href="#">Home</a></li>                <li><a href="#about">About</a></li>                <li><a href="#contact">Contact</a></li>                <li class="dropdown">                   <a href="#" class="dropdown-toogle" data-toogle="dropdown">Dropdown<b class="caret"></b></a>                   <ul class="dropdown-menu">                      <li><a href="#">Action</a></li>                      <li><a href="#">Another Action</a></li>                      <li><a href="#">Something else there</a></li>                      <li class="divider"></li>                      <li class="dropdown-header">Nav header</li>                      <li><a href="#">Separated link</a></li>                      <li><a href="#">One more separated link</a></li>                   </ul>                </li>             </ul>            </div>               </div>    </div>
    <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->    <script src="js/jquery-3.1.1.min.js"></script>    <!-- Include all compiled plugins (below), or include individual files as needed -->    <script src="js/bootstrap.min.js"></script>  </body></html>