跟老师三角形代码一样的,为什么显示不出来? 感谢大神解答!如下:
.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;
}