假设
CONTENT而那CONTENT包括至少一个HTML节点。#content{position:relative}#content:before,#content:after,#content>:first-child:before,#content>:first-child:after{
position:absolute;content:'';
width:80px;height:80px;
border-color:red;/*orwhatevercolour*/
border-style:solid;/*orwhateverstyle*/}#content:before{top:0;left:0;border-width:1px001px}#content:
after{top:0;right:0;border-width:1px1px00}#content>:first-child:before{bottom:0;right:0;border-width:01px1px0}#content>:
first-child:after{bottom:0;left:0;border-width:001px1px}
这是一个小提琴
