Is it possible to make the columns stack on top of each other at widths less than 768px, instead of 991px in Bootstrap 4?
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container-fluid">
<h1>Hello World!</h1>
<p>Resize the browser window to see the effect.</p>
<p>The columns will automatically stack on top of each other when the screen is less than 768px wide.</p>
<div class="row">
<div class="col-sm-4" style="background-color:lavender;">.col-sm-4</div>
<div class="col-sm-4" style="background-color:lavenderblush;">.col-sm-4</div>
<div class="col-sm-4" style="background-color:lavender;">.col-sm-4</div>
</div>
</div>
</body>
</html>