6-sass属性嵌套

.box.box1 {
  width: 300px;
  height: 300px;
  border-top: 1px solid red;
  border-bottom: 1px solid blue;
}

对应的scss写法：

$width:300px;
$height:300px;
.box {
    color: pink;
    &.box1 {
        width: $width;
        height: $height;
        border: {
            top: 1px solid red;
            bottom: 1px solid blue;
        }
    }
}