menu.php

<nav class="navbar navbar-inverse" role="navigation">
   <!-- Brand and toggle get grouped for better mobile display -->
   <div class="navbar-header">
     <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex8-collapse">
       <span class="sr-only">Toggle navigation</span>
       <span class="icon-bar"></span>
       <span class="icon-bar"></span>
       <span class="icon-bar"></span>
     </button>
     <a class="navbar-brand" href="index.php">Watt Meter</a>
   </div>

   <!-- Collect the nav links, forms, and other content for toggling -->
   <div class="collapse navbar-collapse navbar-ex8-collapse">
     <ul class="nav navbar-nav">
       <li class="active"><a href="#">Home</a></li>
       <li><a href="about-us.php">About Us</a></li>
 <li><a href="about-project.php">About the Project</a></li>

     </ul>
   </div><!-- /.navbar-collapse -->
 </nav>