<!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.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">
<h2>表单控件大小</h2>
<p>您可用 .form-control-lg 或 .form-control-sm 更改 .form-control 输入控件的大小：</p>
<form>
<input type="text" class="form-control form-control-lg" placeholder="大型输入控件">
<input type="text" class="form-control mt-3" placeholder="普通输入控件">
<input type="text" class="form-control form-control-sm mt-3" placeholder="小型输入控件">
</form>
</div>
</body>
</html>