%main#main
	.before
	.after
	%ul#one
		%li.one
			.container
				.notification
					%span.before
					%span.after
					%header
						%h2 Messages
						%span.timestamp Now
					.content
						%span.sender Gabrielle Wee
						%span.message Check it out! ✨
						%span.more 2 more messages from Gabrielle
		%li.two
			.container
				.notification
					%span.before
					%span.after
		%li.three
			.container
				.notification
					%span.before
					%span.after
	%ul#two
		%li.one
			.container
				.notification
					%span.before
					%span.after
					%header
						%h2 Calendar
						%span.timestamp 1h ago
					.content
						%span.event WWDC 2018
						%span.date June 4, 2018 at 10:00 AM
						%span.more 2 more invitations
		%li.two
			.container
				.notification
					%span.before
					%span.after
		%li.three
			.container
				.notification
					%span.before
					%span.after
	%ul#three
		%li.one
			.container
				.notification
					%span.before
					%span.after
					%header
						%h2 Twitter
						%span.timestamp 2h ago
					.content
						%span.user Gabrielle Wee
						%span.message Dark Mode for iOS would be so cool!
						%span.more 2 more notifications
		%li.two
			.container
				.notification
					%span.before
					%span.after
		%li.three
			.container
				.notification
					%span.before
					%span.after

$p: 16px;

*, *:before, *:after { box-sizing: border-box; }
::selection { background: none; }
body, html { height: 100vh; }

body {
	display: flex;
	justify-content: center;
	background: #151F33;
	font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans",
    "Droid Sans", "Helvetica Neue", Helvetica, Arial, sans-serif;
	font-size: $p;
	text-rendering: optimizeLegibility;
	-webkit-font-smoothing: antialiased;
}

@media screen and (min-height: 480px) {
	body {
		align-items: center;
		align-content: center;
	}
}

.before, .after {
	will-change: opacity;
	display: block;
	position: absolute;
	top: 0;
	left: 0;
	width: 100vw;
	height: 100vh;
}
.before {
	z-index: -1;
	background: #151F33 url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/345377/mojave-night.jpg') no-repeat center center / cover;
}
.after {
	z-index: -2;
	background: #B27247 url('https://s3-us-west-2.amazonaws.com/s.cdpn.io/345377/mojave-day.jpg') no-repeat center center / cover;
}

main {
	opacity: 0;
	will-change: opacity;
	width: 100%;
	max-width: 400px;
	padding: $p/2;
	.before, .after {
		position: fixed;
	}
}

ul {
	opacity: 0;
	will-change: opacity, transform;
	perspective: 800px;
	margin-bottom: $p;
	li {
		position: relative;
		padding: $p/2;
		&:not(:first-child) {
			position: absolute;
			width: 100%;
			top: 0;
			left: 0;
			.notification {
				.before, .after {
					filter: blur($p);
				}
			}
		}
		&:nth-child(1) {
			z-index: 3;
			.notification {
				background-color: rgba(white, 0.7);
				.before, .after {
					filter: saturate(130%) blur($p);
				}
			}
		}
		&:nth-child(2) {
			transform: translateY($p) translateZ(#{-$p*4});
			z-index: 2;
			.notification {
				background-color: rgba(white, 0.6);
			}
		}
		&:nth-child(3) {
			transform: translateY(#{$p*2}) translateZ(#{-$p*8});
			z-index: 1;
			.notification {
				background-color: rgba(white, 0.5);
			}
		}
	}
}

.container {
	clip-path: inset(0 0 0 0 round $p $p $p $p);
}

.notification {
	position: relative;
	overflow: hidden;
	height: 116px;
	padding: $p;
	border-radius: $p;
	background-color: rgba(white, 0.9);
	color: black;
	header, .more {
		opacity: 0.75;
	}
	header {
		display: flex;
		justify-content: space-between;
		padding-bottom: $p*.5;
		font-size: $p*.75;
		h2 {
			text-transform: uppercase;
		}
		.timestamp {
			text-transform: lowercase;
		}
	}
	.content {
		span {
			display: block;
			line-height: 1.4;
		}
		.message {
			white-space: nowrap;
			overflow: hidden;
			text-overflow: ellipsis;
		}
		.sender, .event {
			font-weight: 600;
		}
		.more {
			margin-top: $p*.25;
			font-size: $p*.75;
		}
	}
	.before, .after {
		left: calc(50% - 50vw);
	}
}

const main = document.querySelector("#main");
const elems = document.querySelectorAll(".notification");

const getTop = el => {
	const before = el.querySelector(".before");
	const after = el.querySelector(".after");
	let viewportOffset = el.getBoundingClientRect();
	let elemTop = viewportOffset.top;
	before.style.top = "-" + elemTop + "px";
	after.style.top = "-" + elemTop + "px";
}

const lightToDark = () => {
	const tl = new TimelineMax();
	const groups = ["#one", "#two", "#three"];
	tl
		.set(".before", {opacity:0})
		.set(groups, {opacity:0,y:60})
		.to(main, 0.5, {opacity:1})
		.staggerTo(groups, 0.5, {opacity:1,ease:Power3.easeOut}, 0.2)
		.staggerTo(groups, 1, {y:0,ease:Power3.easeOut}, 0.2, '-=1')
		.to(".before", 2, {opacity:1})
		.to(".after", 2, {opacity:0}, '-=1')
		.to(".notification", 0.25, {color:"#1b1e29"}, '-=3')
		.to(".notification", 1.75, {color:"white"}, '-=2.75')
		.to(".one .notification", 1, {backgroundColor:"rgba(17,19,26,0.6)"}, '-=3')
		.to(".one .notification", 1, {backgroundColor:"rgba(0,0,0,0.5)"}, '-=2.5')
		.to(".two .notification", 1, {backgroundColor:"rgba(17,19,26,0.5)"}, '-=3')
		.to(".two .notification", 1, {backgroundColor:"rgba(0,0,0,0.4)"}, '-=2.5')
		.to(".three .notification", 1, {backgroundColor:"rgba(17,19,26,0.4)"}, '-=3')
		.to(".three .notification", 1, {backgroundColor:"rgba(0,0,0,0.3)"}, '-=2.5')
	;
}

imagesLoaded(main, {background:true}, () => {
	elems.forEach(el => {
		getTop(el);
		window.addEventListener("resize", function() {
			setTimeout(() => {
				getTop(el);
			}, 250);
		});
	});
	window.requestAnimationFrame(lightToDark);
});