NAVBAR TOGGLE BUTTON
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<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap </title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.1/dist/css/bootstrap.min.css" rel="stylesheet"> 
  <script src="https://cdn.jsdelivr.net/npm/@popperjs/core@2.9.2/dist/umd/popper.min.js" integrity="sha384-IQsoLXl5PILFhosVNubq5LC7Qb9DXgDA9i+tQ8Zj3iwWAwPtgFTxbJ8NT4GN1R8p" crossorigin="anonymous"></script>
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.0.1/dist/js/bootstrap.min.js" integrity="sha384-Atwg2Pkwv9vp0ygtn1JAojH0nYbwNJLPhwyoVbhoPwBhjQPR5VtM2+xf0Uwh9KtT" crossorigin="anonymous"></script></head>
<body>
    
	<nav class="navbar navbar-expand-lg navbar-dark bg-dark">
	  <div class="container-fluid">
		<a class="navbar-brand" href="#">Navbar</a>
		<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarSupportedContent" >
		  <span class="navbar-toggler-icon"></span>
		</button>
		<div class="collapse navbar-collapse" id="navbarSupportedContent">
		  <ul class="navbar-nav ">
			<li class="nav-item">
			  <a class="nav-link active" aria-current="page" href="#">Home</a>
			</li>
			<li class="nav-item">
			  <a class="nav-link" href="#">Course</a>
			</li>
		  </ul>
		  
		</div>
	  </div>
	</nav>
	
</body>
</html>