// Mixins
$breakpoints: (
  'small'     : 768px,
  'small-800' : 800px,
  'medium'    : 992px,
  'large'     : 1200px
);

/* Usage:
 *
 * @include breakpoint(small) { ... }
 * @include breakpoint(medium) { ... }
 * @include breakpoint(large) { ... }
 *
 */
@mixin breakpoint($breakpoint) {
  // Retrieves the value from the key
  $value: map-get($breakpoints, $breakpoint);

  // If the key exists in the map
  @if $value != null {
    // Prints a media query based on the value
    @media (min-width: $value) {
      @content;
    }
  }

  // If the key doesn't exist in the map
  @else {
    @warn "Unfortunately, no value could be retrieved from `#{$breakpoint}`. "
        + "Please make sure it is defined in `$breakpoints` map.";
  }
}

/* Usage:
 *
 * @include placeholder { ... }
 *
 */
@mixin placeholder {
  // Chrome/Opera/Safari 
  &::-webkit-input-placeholder {
    opacity: 1;
    @content;
  }

  // Firefox 19+
  &::-moz-placeholder {
    opacity: 1;
    @content;
  }

  // IE 10+
  &:-ms-input-placeholder {
    opacity: 1;
    @content;
  }

  // Firefox 18-
  &:-moz-placeholder {
    opacity: 1;
    @content;
  }
}