@mixin transition($time) {

  -webkit-transition: all $time;
  -moz-transition: all $time;
  -ms-transition: all $time;
  -o-transition: all $time;
  transition: all $time;
}

@keyframes up_slide {
  100% { right: 20px; opacity: 1; }

  50% {opacity: 0.4;}
}

@keyframes up_slide_out {
  100% { right: -100%; opacity: 0; }

  50% {opacity: 0.4;}
}