SASS Media Query demo

@mixin for-phone-only {
  @media (max-width: 599px) {
    @content;
  }
}

@mixin for-tablet-portrait-up {
  @media (min-width: 600px) {
    @content;
  }
}

@mixin for-tablet-landscape-up {
// vvv FIXED MISSING `@` vvv
  @media (min-width: 900px) {
    @content;
  }
}

@mixin for-desktop-up {
  @media (min-width: 1200px) {
    @content;
  }
}

@mixin for-big-desktop-up {
  @media (min-width: 1800px) {
    @content;
  }
}


// EXAMPLE.SCSS
body {
  font-family: Helvetica;

  @include for-phone-only {
    background-color:red;
  }
}


// RESULT.CSS
body {
  font-family: Helvetica;
}

@media (max-width: 599px) {
  body {
    background-color: red;
  }
}