bootstrap文本类设置

<h1 class="display-1">display1</h1>
<h1 class="display-2">display2</h1>
<h1 class="display-3">display3</h1>
<h1 class="display-4">display4</h1>
<!--使用六个类名h1-h6来让非标题元素实现标题效果-->
<div class="h1">一级标题</div>
<div class="h2">二级标题</div>
<div class="h3">三级标题</div>
<div class="h4">四级标题</div>
<div class="h5">五级标题</div>
<div class="h6">六级标题</div>
<!--副标题类-->
<h1>一级标题<small>我是副标题</small></h1>
<h1>一级标题<small class="test-muted">我是副标题</small></h1>