DIV简约框框
瓜皮之牙 
<nav class="navbar navbar-light bg-light">
  <span class="navbar-text">
    Navbar text with an inline element
  </span>
</nav>

<div class="card text-auto">
<div class="card-body">
瓜皮之牙
</div>
</div>
下面是间距较小的DIV框架
瓜皮之牙 
<div class='border rounded p-2 mt-3' style='background-color:#D6EAFF;' >
瓜皮之牙
</div>