@mixin transition($time) {
  transition: all $time;
}

@mixin transform($value) {
  transform: $value;
}
@mixin border-radius($value) {
  border-radius: $value;
}

// Placeholder Mixins
@mixin placeholder {
  &::placeholder {
    @content;
  }
}

// media queries
$units: 1px !default;

@mixin max-screen($res-first, $res-last: $res-first) {
  @if $res-first == $res-last {
    @media screen and (max-width: if(unitless($res-first), $res-first*$units, $res-first)) {
      @content;
    }
  } @else if $res-first < $res-last {
    @media screen and (min-width: if(unitless($res-first), $res-first*$units, $res-first)) and (max-width: if(unitless($res-last), $res-last*$units, $res-last)) {
      @content;
    }
  }
}

@mixin min-screen($res) {
  @media screen and (min-width: if(unitless($res), $res*$units, $res)) {
    @content;
  }
}