代码示例：（标识：bs_navbar_centered）
<!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.bundle.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>
<div class="container-fluid mt-3">
<h3>居中的导航栏</h3>
<p>请使用 .justify-content-center 类将导航栏居中。</p>
<p>在这个例子中，导航栏将在中、大和超大屏幕上居中。在小屏幕上，它将垂直和左对齐显示（由于 .navbar-expand-sm 类）。</p>
</div>
</body>
</html>
