@mixin keyframes ($name) {
	@-webkit-keyframes #{$name} {
		@content;
	}
	@-moz-keyframes #{$name} {
		@content;
	}
}

@include keyframes("fade-in") {
	0% {opacity: 0;}
	20%   , 50%,100%{opacity: 1;}
	30%, 75% {opacity: 0;}
}