I'm trying to add a bootstrap accordion to this webpage, and I'm not sure why these buttons aren't working.
My code:
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" />
<div class="accordion" id="myAccordion">
<div class="card">
<div class="card-header" id="headingOne">
<h2 class="mb-0">
<button class="btn btn-link" type="button" data-toggle="collapse" data-target="#collapseOne">HTML5</button>
</h2>
</div>
<div id="collapseOne" class="collapse show" data-parent="#myAccordion">
<div class="card-body">
HTML5 is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and latest major version of HTML that is a World Wide Web Consortium (W3C) recommendation.
</div>
</div>
</div>
<div class="card">
<div class="card-header" id="headingTwo">
<h2 class="mb-0">
<button class="btn btn-link collapsed" type="button" data-toggle="collapse" data-target="#collapseTwo">CSS3</button>
</h2>
</div>
<div id="collapseTwo" class="collapse" data-parent="#myAccordion">
<div class="card-body">
CSS3 is the latest evolution of the Cascading Style Sheets language and aims at extending CSS2. 1. It brings a lot of long-awaited novelties, like rounded corners, shadows, gradients, transitions or animations, as well as new layouts like multi-columns,
flexible box or grid layouts.
</div>
</div>
</div>
<div class="card">
<div class="card-header" id="headingThree">
<h2 class="mb-0">
<button class="btn btn-link collapsed" type="button" data-toggle="collapse" data-target="#collapseThree">Responsive Design</button>
</h2>
</div>
<div id="collapseThree" class="collapse" data-parent="#myAccordion">
<div class="card-body">
Responsive web design (RWD) is a web development approach that creates dynamic changes to the appearance of a website, depending on the screen size and orientation of the device being used to view it. ... In responsive design, page elements reshuffle
as the viewport grows or shrinks.
</div>
</div>
</div>
</div>
add bootstrap 4 and js file use