input.sass

.one
  color: red
  .two
    color: red
    .three
      color: red
      .four
        color: red
        .five
          color: red
          .six
            color: red
            .seven
              color: red

output.css

.one {
  color: red;
}
.one .two {
  color: red;
}
.one .two .three {
  color: red;
}
.one .two .three .four {
  color: red;
}
.one .two .three .four .five {
  color: red;
}
.two .three .four .five .six {
  color: red;
}
.three .four .five .six .seven {
  color: red;
}