Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.21)
// Compass (v1.0.3)
// ----

.block {
  display: block;

  @at-root {

    .block__element {
      font-size: 18px;
      color: green;
      
      &.block__element--modifier {
        color: blue;
  
        .android-webkit & {
          color: pink;
        }
      }
    }

  }
  
}

SassMeister-output.css

.block {
  display: block;
}
.block__element {
  font-size: 18px;
  color: green;
}
.block__element.block__element--modifier {
  color: blue;
}
.android-webkit .block__element.block__element--modifier {
  color: pink;
}