css3给::after添加hover伪类 before同理

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div {position:relative;width:100px;height:100px;border:1px solid #ccc;}div::after {content:\"\";position:absolute;top:50px;right:-5px;border-left:5px solid #ccc;border-top:5px solid  transparent;border-bottom:5px solid transparent;}div:hover::after {border-left:5px solid red;}div:hover {background-color:red;}