next.js/examples/page-transitions/static/style.css

body, html {
	margin: 0;
	padding: 0;
}

body {
	background: #000;
}

/* ------------------------------------------- */

header {
	z-index: 100;
	position: fixed;
	right: 0;
	top: 20px;
	left: 0;
	text-align: center;
	padding: 15px;
}

	header a {
		color: blue;
	}

	header a:not(:last-child) {
		margin-right: 15px;
	}

	header a.active {
		color: #000;
		text-decoration: none;
	}

/* ------------------------------------------- */

@keyframes animateIn {
	from {
		transform: translate3d(100vw, 0, 0);;
	}

	to {
		transform: translate3d(0, 0, 0);
	}
}

@keyframes animateOut {
	to {
		transform: translate3d(-100vw, 0, 0);
	}
}

@keyframes fadeIn {
	to {
		opacity: 1;
	}
}

/* ------------------------------------------- */

#container {
	display: flex;
	align-items: center;
	justify-content: center;
	width: 100%;
	height: 100vh;
	box-shadow: inset 0 0 0 20px;
	background: #FFF;
}

	#container.page-about {
		background: tan;
	}

	#container.page-contact {
		background: violet;
	}

	#container h1 {
		font-size: 10vw;
		text-transform: uppercase;
		letter-spacing: -1px;
	}

#container[class*="animate-"] {
	position: fixed;
	animation: animateIn .75s ease-in-out forwards;
	transform-origin: center;
	will-change: transform;
}

	#container.animate-out {
		animation-name: animateOut;
	}

.loading #container:not(.clone) h1 {
	opacity: 0;
	animation: fadeIn 1s .15s ease-in-out forwards;
}