// Animation Fill Mode
//
// The animation-fill-mode property defines what values are applied by the
// animation outside the time it is executing.
//
// Values: none | forwards | backwards | both
// Default: none
//
// https://www.w3.org/TR/css-animations-1/#animation-fill-mode
@mixin animation-fill-mode($value: none) {
  -webkit-animation-fill-mode: $value;
     -moz-animation-fill-mode: $value;
       -o-animation-fill-mode: $value;
          animation-fill-mode: $value;
}