<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 示例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.cn/lib/bootstrap/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.5.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://www.w3schools.cn/lib/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h1>左侧外边距实用程序</h1>
<p>左侧外边距实用程序:</p>
<div class="ml-0 bg-warning">左侧外边距 0</div>
<div class="ml-1 bg-warning">左侧外边距 1</div>
<div class="ml-2 bg-warning">左侧外边距 2</div>
<div class="ml-3 bg-warning">左侧外边距 3</div>
<div class="ml-4 bg-warning">左侧外边距 4</div>
<div class="ml-5 bg-warning">左侧外边距 5</div>
<div class="ml-auto bg-warning" style="width:150px">自动左侧外边距</div>
<p>响应式右侧外边距实用程序。 调整浏览器窗口大小看看效果：</p>
<div class="ml-sm-5 bg-warning">SM 屏幕上的左边距 5</div>
<div class="ml-md-5 bg-warning">MD 屏幕上的左边距 5</div>
<div class="ml-lg-5 bg-warning">LG 屏幕上的左边距 5</div>
<div class="ml-xl-5 bg-warning">XL 屏幕上的左边距 5</div>
</div>
</body>
</html>