少继承不行

只需添加单词 全部的 类名称旁边

.child-item {
  &:extend(.parent-item all);
  //...
}

例如

.parent-item {
  color: green;
  background: red;
  &:not(:last-child) {
    margin-right: 20px;
  }

  &:last-child {
    color: red;
  }

  &:hover {
    color: red;
  }
}




.child-item {
  &:extend(.parent-item all);
  //...
}

结果将是

.parent-item,
.child-item {
  color: green;
  background: red;
}
.parent-item:not(:last-child),
.child-item:not(:last-child) {
  margin-right: 20px;
}
.parent-item:last-child,
.child-item:last-child {
  color: red;
}
.parent-item:hover,
.child-item:hover {
  color: red;
}