css-breakpoint-mixin-1.scss

@mixin for-size($size) {
  @if $size == phone-only {
    @media (max-width: 599px) { @content; }
  } @else if $size == tablet-portrait-up {
    @media (min-width: 600px) { @content; }
  } @else if $size == tablet-landscape-up {
    @media (min-width: 900px) { @content; }
  } @else if $size == desktop-up {
    @media (min-width: 1200px) { @content; }
  } @else if $size == big-desktop-up {
    @media (min-width: 1800px) { @content; }
  }
}

// usage
.my-box {
  padding: 10px;
  
  @include for-size(desktop-up) {
    padding: 20px;
  }
}

css-breakpoint-mixin.sass

@mixin for-size($size)
  @if $size == phone-only
    @media (max-width: 599px)
      @content
  @else if $size == tablet-portrait-up 
    @media (min-width: 600px) 
      @content
  @else if $size == tablet-landscape-up
    @media (min-width: 900px) 
      @content
  @else if $size == desktop-up
    @media (min-width: 1200px)
      @content
  @else if $size == big-desktop-up
    @media (min-width: 1800px) 
      @content

// usage
.my-box
  padding: 10px
  
  @include for-size(desktop-up)
    padding: 20px