代码示例：（标识：bs_card_contextual）
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="p-4">
<h2>设置上下文类的</h2>
<div class="card">
<div class="card-body">Basic card</div>
</div>
<br>
<div class="card bg-primary text-white">
<div class="card-body">Primary card</div>
</div>
<br>
<div class="card bg-success text-white">
<div class="card-body">Success card</div>
</div>
<br>
<div class="card bg-info text-white">
<div class="card-body">Info card</div>
</div>
<br>
<div class="card bg-warning text-white">
<div class="card-body">Warning card</div>
</div>
<br>
<div class="card bg-danger text-white">
<div class="card-body">Danger card</div>
</div>
<br>
<div class="card bg-secondary text-white">
<div class="card-body">Secondary card</div>
</div>
<br>
<div class="card bg-dark text-white">
<div class="card-body">Dark card</div>
</div>
<br>
<div class="card bg-light text-dark">
<div class="card-body">Light card</div>
</div>
</div>
</body>
</html>
