<!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 href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.2/dist/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.2/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h1>上下外边距 Utility</h1>
<p>Margin Y utilities:</p>
<div class="my-0 bg-warning">Margin Y 0</div>
<div class="my-1 bg-warning">Margin Y 1</div>
<div class="my-2 bg-warning">Margin Y 2</div>
<div class="my-3 bg-warning">Margin Y 3</div>
<div class="my-4 bg-warning">Margin Y 4</div>
<div class="my-5 bg-warning">Margin Y 5</div>
<div class="my-auto bg-warning">Margin Y Auto</div>
<br>
<p>响应式 margin y 实用工具。请调整浏览器窗口大小以查看效果：</p>
<div class="my-sm-5 bg-warning">在 SM 屏幕上的 Margin Y 5</div>
<div class="my-md-5 bg-warning">在 MD 屏幕上的 Margin Y 5</div>
<div class="my-lg-5 bg-warning">在 LG 屏幕上的 Margin Y 5</div>
<div class="my-xl-5 bg-warning">在 XL 屏幕上的 Margin Y 5</div>
</div>
</body>
</html>