html {
	box-sizing: border-box;
	background: #ffc600;
	font-family: "helvetica neue";
	font-size: 20px;
	font-weight: 200;
}

body {
	margin: 0;
}

*,
*:before,
*:after {
	box-sizing: inherit;
}

.panels {
	min-height: 100vh;
	overflow: hidden;
	display: flex;
}

.panel {
	background: #6b0f9c;
	box-shadow: inset 0 0 0 5px rgba(255, 255, 255, 0.1);
	color: white;
	text-align: center;
	align-items: center;
	/* Safari transitionend event.propertyName === flex */
	/* Chrome + FF transitionend event.propertyName === flex-grow */
	transition: font-size 0.7s cubic-bezier(0.61, -0.19, 0.7, -0.11),
		flex 0.7s cubic-bezier(0.61, -0.19, 0.7, -0.11), background 0.2s;
	font-size: 20px;
	background-size: cover;
	background-position: center;
	flex: 1;
	justify-content: center;
	align-content: center;
	display: flex;
	flex-direction: column;
}

.panel1 {
	background-image: url(https://source.unsplash.com/gYl-UtwNg_I/1500x1500);
}
.panel2 {
	background-image: url(https://source.unsplash.com/rFKUFzjPYiQ/1500x1500);
}
.panel3 {
	background-image: url(https://images.unsplash.com/photo-1465188162913-8fb5709d6d57?ixlib=rb-0.3.5&q=80&fm=jpg&crop=faces&cs=tinysrgb&w=1500&h=1500&fit=crop&s=967e8a713a4e395260793fc8c802901d);
}
.panel4 {
	background-image: url(https://source.unsplash.com/ITjiVXcwVng/1500x1500);
}
.panel5 {
	background-image: url(https://source.unsplash.com/3MNzGlQM7qs/1500x1500);
}

/* Flex Children */
.panel > * {
	margin: 0;
	width: 100%;
	transition: transform 0.5s;
	flex: 1 0 auto;
	display: flex;
	justify-content: center;
	align-items: center;
}

.panel > *:first-child {
	transform: translateY(-100%);
}

.panel.open-active > *:first-child {
	transform: translateY(0%);
}

.panel > *:last-child {
	transform: translateY(100%);
}

.panel.open-active > *:last-child {
	transform: translateY(0%);
}

.panel p {
	text-transform: uppercase;
	font-family: "Amatic SC", cursive;
	text-shadow: 0 0 4px rgba(0, 0, 0, 0.72), 0 0 14px rgba(0, 0, 0, 0.45);
	font-size: 2em;
}

.panel p:nth-child(2) {
	font-size: 4em;
}

.panel.open {
    font-size: 40px;
    flex:5;
}