Create a CSS Flipping Animation

CSS animations are a lot of fun; the beauty of them is that through many simple properties, you can create anything from an elegant fade in to a WTF-Pixar-would-be-proud effect. One CSS effect somewhere in between is the CSS flip effect, whereby there's content on both the front and back of a given container. This tutorial will show you show to create that effect in as simple a manner as possible.

Quick note: this is not the first tutorial about this effect, but I've found the others over-complicated. Many other tutorials add additional styles to code samples which then require the reader to decipher which are needed and which aren't. This tutorial avoids that issue, providing you only the necessary styles; you can pretty up each side of the flip any way you'd like.

The HTML

The HTML structure to accomplish the two-sided effect is as you would expect it to be:

<div class="flip-container" ontouchstart="this.classList.toggle('hover');">
	<div class="flipper">
		<div class="front">
			<!-- front content -->
		</div>
		<div class="back">
			<!-- back content -->
		</div>
	</div>
</div>

There are two content panes, "front" and "back", as you would expect, but also two containing elements with very specific roles explained by their CSS. Also note the ontouchstart piece which allows the panes to swap on touch screens. Obviously you should break that code into a separate, unobtrusive JavaScript block if you wish.

The CSS

I'm willing to bet that outside of the usual vendor prefix bloat, you'd be surprised at how little CSS is involved:

/* entire container, keeps perspective */
.flip-container {
	perspective: 1000;
}
	/* flip the pane when hovered */
	.flip-container:hover .flipper, .flip-container.hover .flipper {
		transform: rotateY(180deg);
	}

.flip-container, .front, .back {
	width: 320px;
	height: 480px;
}

/* flip speed goes here */
.flipper {
	transition: 0.6s;
	transform-style: preserve-3d;

	position: relative;
}

/* hide back of pane during swap */
.front, .back {
	backface-visibility: hidden;

	position: absolute;
	top: 0;
	left: 0;
}

/* front pane, placed above back */
.front {
	z-index: 2;
}

/* back, initially hidden pane */
.back {
	transform: rotateY(180deg);
}

Here's a rough overview of the process:

• The outlying container sets the entire animation area's perspective
• The inner container is the element that actually flips, spinning 180 degrees when the parent container is hovered over. This is also where you control the transition speed. Changing the rotation to -180deg spins the elements in the reverse direction.
• The front and back elements are positioned absolutely so they can "overlay" each other in the same position; their backface-visibility is hidden so the back of the flipped elements don't display during the animation
• The front element has a higher z-index than the back element so the front element may be coded first but it still displays on top
• The back element is rotate 180 degrees, so as to act as the back.

That's really all there is to it!Put this simple structure into place and then style each side as you'd like!

The CSS flip animation has always been a classic, representative example of what's possible with CSS animations, and to a lessor extent, 3D CSS animations. What's better is that there's actually very little CSS involved. This effect would be really neat for HTML5 games, and as a standalone "card" effect, it's perfect. Can you think of anything else you'd use this for?