Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.1)
// Compass (v0.13.alpha.10)
// ----

@media all {
        %all-grid { content:'all';}
    }
    @media (max-width:480px){
        %mobile-grid-col  { content:'mobile-grid-col';}
        %mobile-grid-span { content:'mobile-grid-span';}
    }
    
    
    // 
    @media (max-width:480px){
        .bar { @extend %mobile-grid-span; @extend %mobile-grid-col; }
    }
    .bar { @extend %all-grid; }

SassMeister-output.css

@media all {
  .bar {
    content: 'all';
  }
}
@media (max-width: 480px) {
  .bar {
    content: 'mobile-grid-col';
  }

  .bar {
    content: 'mobile-grid-span';
  }
}