<div class="shadow-none p-3 mb-5 bg-light rounded">No shadow</div>
<div class="shadow-sm p-3 mb-5 bg-body rounded">Small shadow</div>
<div class="shadow p-3 mb-5 bg-body rounded">Regular shadow</div>
<div class="shadow-lg p-3 mb-5 bg-body rounded">Larger shadow</div>

附加知识点：将框架固定宽度（和Quicker页面相同宽度）
只需将代码换成 <div class="shadow-lg p-3 mb-5 bg-body rounded container"> 即可。