代码示例：（标识：bs_modal_fullscreen_xxl）
<!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>
<div class="p-4">
<h3>响应式全屏模态实例</h3>
<p>modal-fullscreen-xxl-down 类将显示低于 1400px 的全屏模式。</p>
<p>请单击该按钮并调整浏览器窗口的大小以查看效果。</p>
<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#myModal">
打开模态
</button>
</div>
<!-- 模态 -->
<div class="modal" id="myModal">
<div class="modal-dialog modal-fullscreen-xxl-down">
<div class="modal-content">
<!-- 模态标题 -->
<div class="modal-header">
<h4 class="modal-title">模态标题</h4>
<button type="button" class="btn-close" data-bs-dismiss="modal"></button>
</div>
<!-- 模态主体 -->
<div class="modal-body">
模态主体..
</div>
<!-- 模态页脚 -->
<div class="modal-footer">
<button type="button" class="btn btn-danger" data-bs-dismiss="modal">关闭</button>
</div>
</div>
</div>
</div>
</body>
</html>
