<!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>
<nav class="navbar navbar-expand-sm bg-light justify-content-center">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="#">链接 1</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">链接 2</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">链接 3</a>
</li>
</ul>
</nav>
<br>
<div class="container-fluid">
<h3>居中导航栏</h3>
<p>使用 .justify-content-center 类使导航栏居中。</p>
<p>在此示例中，导航栏将在中型、大型和超大型屏幕上居中。 在小屏幕上，它将垂直显示并左对齐（因为 .navbar-expand-sm 类）。</p>
</div>
</body>
</html>