sp-magic.de/bower_components/foundation-sites/scss/components/_visibility.scss

// Foundation for Sites by ZURB
// foundation.zurb.com
// Licensed under MIT Open Source

/// Hide an element by default, only displaying it above a certain screen size.
/// @param {Keyword} $size - Breakpoint to use. **Must be a breakpoint defined in `$breakpoints`.**
@mixin show-for($size) {
  $size: map-get($breakpoints, $size);
  $size: -zf-bp-to-em($size) - (1 / 16);

  @include breakpoint($size down) {
    display: none !important;
  }
}

/// Hide an element by default, only displaying it within a certain breakpoint.
/// @param {Keyword} $size - Breakpoint to use. **Must be a breakpoint defined in `$breakpoints`.**
@mixin show-for-only($size) {
  $lower-bound-size: map-get($breakpoints, $size);
  $upper-bound-size: -zf-map-next($breakpoints, $size);

  // more often than not this will be correct, just one time round the loop it won't so set in scope here
  $lower-bound: -zf-bp-to-em($lower-bound-size) - (1 / 16);
  // test actual lower-bound-size, if 0 set it to 0em
  @if strip-unit($lower-bound-size) == 0 {
    $lower-bound: -zf-bp-to-em($lower-bound-size);
  }

  @if $upper-bound-size == null {
    @media screen and (max-width: $lower-bound) {
      display: none !important;
    }
  }
  @else {
    $upper-bound: -zf-bp-to-em($upper-bound-size);

    @media screen and (max-width: $lower-bound), screen and (min-width: $upper-bound) {
      display: none !important;
    }
  }
}


/// Show an element by default, and hide it above a certain screen size.
/// @param {Keyword} $size - Breakpoint to use. **Must be a breakpoint defined in `$breakpoints`.**
@mixin hide-for($size) {
  @include breakpoint($size) {
    display: none !important;
  }
}

/// Show an element by default, and hide it above a certain screen size.
/// @param {Keyword} $size - Breakpoint to use. **Must be a breakpoint defined in `$breakpoints`.**
@mixin hide-for-only($size) {
  @include breakpoint($size only) {
    display: none !important;
  }
}

@mixin foundation-visibility-classes {
  // Basic hiding classes
  .hide {
    display: none !important;
  }

  .invisible {
    visibility: hidden;
  }

  // Responsive visibility classes
  @each $size in $breakpoint-classes {
    @if $size != $-zf-zero-breakpoint {
      .hide-for-#{$size} {
        @include hide-for($size);
      }

      .show-for-#{$size} {
        @include show-for($size);
      }
    }

    .hide-for-#{$size}-only {
      @include hide-for-only($size);
    }

    .show-for-#{$size}-only {
      @include show-for-only($size);
    }
  }

  // Screen reader visibility classes
  // Need a "hide-for-sr" class? Add aria-hidden='true' to the element
  .show-for-sr,
  .show-on-focus {
    @include element-invisible;
  }

  // Only display the element when it's focused
  .show-on-focus {
    &:active,
    &:focus {
      @include element-invisible-off;
    }
  }

  // Landscape and portrait visibility
  .show-for-landscape,
  .hide-for-portrait {
    display: block !important;

    @include breakpoint(landscape) {
      display: block !important;
    }

    @include breakpoint(portrait) {
      display: none !important;
    }
  }

  .hide-for-landscape,
  .show-for-portrait {
    display: none !important;

    @include breakpoint(landscape) {
      display: none !important;
    }

    @include breakpoint(portrait) {
      display: block !important;
    }
  }
}