在a:after 之后的css效果显示不出来是什么原因?浏览器的原因吗?
.st-container input:checked + a:after{
content:"";
width:0;
height:0;
overflow: hidden;
border:20px solid transparent;
border-bottom-color:#821134;
position: absolute;
bottom: 100%
left:50%;
margin-left: -20px;
}
<div class="st-container">
<input type="radio" name="radio-set" checked="checked" id="st-control-1">
<a href="#st-panel-1">Serendipity</a>