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; }