1.子元素范围选择 举例

.iconList_wr li:nth-child(n + 1):nth-child(-n + 4) {
     margin-right: 0.6rem;}.iconList_wr li:nth-child(5) {
     margin-left: 1.04rem;}.iconList_wr li:nth-child(n + 4) ~ li {
     margin-right: 0.6rem;  margin-top: 0.4rem;}