1：简单的卡片
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/4.1.0/css/bootstrap.min.css">
<script src="https://cdn.staticfile.org/jquery/3.2.1/jquery.min.js"></script>
<script src="https://cdn.staticfile.org/popper.js/1.12.5/umd/popper.min.js"></script>
<script src="https://cdn.staticfile.org/twitter-bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>简单的卡片</h2>
<div class="card">
<div class="card-body">简单的卡片</div>
</div>
</div>
</body>
</html>
2：头部和底部
.card-header类用于创建卡片的头部样式， .card-footer 类用于创建卡片的底部样式：
<div class="container">
<h2>卡片头部和底部</h2>
<div class="card">
<div class="card-header">头部</div>
<div class="card-body">内容</div>
<div class="card-footer">底部</div>
</div>
</div>
3：多种颜色卡片
Bootstrap 4 提供了多种卡片的背景颜色类： .bg-primary, .bg-success, .bg-info, .bg-warning, .bg-danger, .bg-secondary, .bg-dark 和 .bg-light。
<div class="container">
<h2>多种颜色卡片</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>
4：标题、文本和链接
我们可以在头部元素上使用 .card-title 类来设置卡片的标题 。 .card-text 类用于设置卡片正文的内容。 .card-link 类用于给链接设置颜色。
<div class="container">
<h2>标题、文本和链接</h2>
<div class="card">
<div class="card-body">
<h4 class="card-title">Card title</h4>
<p class="card-text">Some example text. Some example text.</p>
<a href="#" class="card-link">Card link</a>
<a href="#" class="card-link">Another link</a>
</div>
</div>
</div>
5：图片卡片
我们可以给 <img> 添加 .card-img-top（图片在文字上方） 或 .card-img-bottom（图片在文字下方 来设置图片卡片：
<div class="container">
<h2>图片卡片</h2>
<p>图片在头部 (card-img-top):</p>
<div class="card" style="width:400px">
<img class="card-img-top" src="https://static.runoob.com/images/mix/img_avatar.png" alt="Card image" style="width:100%">
<div class="card-body">
<h4 class="card-title">John Doe</h4>
<p class="card-text">Some example text some example text. John Doe is an architect and engineer</p>
<a href="#" class="btn btn-primary">See Profile</a>
</div>
</div>
<br>
<p>图片在底部(card-img-bottom):</p>
<div class="card" style="width:400px">
<div class="card-body">
<h4 class="card-title">Jane Doe</h4>
<p class="card-text">Some example text some example text. Jane Doe is an architect and engineer</p>
<a href="#" class="btn btn-primary">See Profile</a>
</div>
<img class="card-img-bottom" src="https://static.runoob.com/images/mix/img_avatar.png" alt="Card image" style="width:100%">
</div>
</div>
如果图片要设置为背景，可以使用 .card-img-overlay 类:
<div class="container">
<h2>文字覆盖图片</h2>
<p>如果图片要设置为背景，可以使用 .card-img-overlay 类:</p>
<div class="card img-fluid" style="width:500px">
<img class="card-img-top" src="https://static.runoob.com/images/mix/img_avatar.png" alt="Card image" style="width:100%">
<div class="card-img-overlay">
<h4 class="card-title">John Doe</h4>
<p class="card-text">Some example text some example text. Some example text some example text. Some example text some example text.
Some example text some example text.</p>
<a href="#" class="btn btn-primary">See Profile</a>
</div>
</div>
</div>