Generated by SassMeister.com, the Sass playground.

SassMeister-input.scss

// Sass v3.2.3
// Stipe v0.0.5.4/n/n@import "./sass/stipe";

.block {
  width: 80em;
  @media #{$mobile} {
    width: 100%;
  }
}

.foo {
  background: orange;
  @media #{$mobile} {
    background: green;
  }
}

SassMeister-output.css

.block {
  width: 80em;
}
@media screen and (max-width: 40em) {
  .block {
    width: 100%;
  }
}

.foo {
  background: orange;
}
@media screen and (max-width: 40em) {
  .foo {
    background: green;
  }
}