题解 | #CSS选择器——伪元素#

{"css":"/*补全代码*/\ndiv::after{\n    content: 'x';\n    height: 20px;\n    width: 20px;\n    background-color: rgb(255,0,0);\n    display: block\n}","js":"","html":"<div></div>","libs":[]}

后伪元素内需要添加content才能通过