div div { ???????????background: orange; ???????} ???????????????body>div { ???????????background: green; ???????} ???????????????.active+div { ???????????background: lime; ???????} ???????????????.active~div { ???????????background: red; ???????}div div ：说明div标签与div标签才生效
body>div：说明body下面的div标签全部生效
.active+div:说明active类下面的第一个div生效
.active~div:说明active类下面的所有div都生效
css3 - 层次选择器
原文地址：https://www.cnblogs.com/cisum/p/8849227.html