/* 三角形 */
.comment-body > div{
position: relative;
left:3.67vw;
content: "";
width: 0;
height: 0;
border-bottom: 0.6rem solid rgb(238, 238, 238);
border-right: 0.6rem solid transparent;
border-top: 0.1rem solid transparent;
border-left: 0.6rem solid transparent;
}
效果(矩形上面的小三角形):
