1<===> input.scss
2@mixin foo() {
3  @media (mix-width: 100px) {
4    @extend %bar;
5  }
6}
7
8foo {
9  @media (mix-width: 100px) {
10    %bar {
11      foo: bar;
12    }
13  }
14
15  @include foo;
16}
17
18<===> output.css
19@media (mix-width: 100px) {
20  foo foo {
21    foo: bar;
22  }
23}
24