Answers for "fade in fade out show div"

css fade in and stay

.fadePopInAndStay {
	display: block;
	opacity: 0;
	visibility: visible;
	animation-name: doAnimStay;
	animation-duration: 2s;
	animation-fill-mode: forwards;/* Makes it stay after animation */
}
@-webkit-keyframes doAnimStay{
  0%   {opacity:0;}
  100% {opacity:1;}
}

fade div

Copy.box {
  -webkit-mask-image: linear-gradient(to bottom, black 0%, transparent 100%);
  mask-image: linear-gradient(to bottom, black 0%, transparent 100%);
}