@mixin appearance($value) {
  -webkit-appearance: $value;
  -ms-appearance: $value;
  -o-appearance: $value;
  -ms-appearance: $value;
  appearance: $value;
}

@mixin transition($value) {
  -webkit-transition: $value;
  -ms-transition: $value;
  -o-transition: $value;
  -ms-transition: $value;
  transition: $value;
}

@mixin animation($value) {
  -webkit-animation: $value;
  -ms-animation: $value;
  -o-animation: $value;
  -ms-animation: $value;
  animation: $value;
}

@mixin box-shadow($value) {
  -webkit-box-shadow: $value;
  -o-box-shadow: $value;
  -ms-box-shadow: $value;
  box-shadow: $value;
}

@mixin calc($property, $expression) {
  #{$property}: -webkit-calc( #{$expression} );
  #{$property}: -moz-calc( #{$expression} );
  #{$property}: calc( #{$expression} );
}