/*ony for one corner, use this variable several time for other corners*/
.fade {
  opacity: 0;
  -webkit-transition: opacity 0.2s linear;
  -moz-transition: opacity 0.2s linear;
  -ms-transition: opacity 0.2s linear;
  -o-transition: opacity 0.2s linear;
  transition: opacity 0.2s linear;
}
.fade.in {
  opacity: 1;
}