chromium/third_party/blink/web_tests/external/wpt/css/css-flexbox/interactive/flexbox_interactive_order-transitions.html

<!DOCTYPE html>
<title>flexbox | flex-flow and transitioned order</title>
<link rel="author" href="http://opera.com" title="Opera Software">
<link rel="help" href="http://www.w3.org/TR/css-flexbox-1/#flex-property">
<meta name="flags" content="interact">
<style>
div {
	background: blue;
	padding: 0;
	margin: 1em 0;
	border: 1px solid black;
	width: 20em;
	height: 8em;

	display: flex;
	flex-flow: column-reverse wrap-reverse;
}
span {
	background: white;
	margin: 1em;
	width: 8em;
	height: 1.5em;
	display: inline-block;
}
.one {
	background: pink;
	order: -1;
}
div:hover .one {
	transition: order 4s;
	order: 4;
}
.two {
	background: yellow;
	order: 3;
}
.three {
	background: black;
	color: white;
	order: 2;
}
.four {
	background: fuchsia;
	color: white;
	order: 1;
}
p~div {
	padding: 1em 0 0;
	margin-right: 1em;
	height: 7em;
	float: left;
	display: block;
}
p~div span {
	float: left;
}
</style>

<div>
	<span class="one">one</span>
	<span class="two">two</span>
	<span class="three">three</span>
	<span class="four">four</span>
</div>

<p>Verify that the box above looks exactly like the first of the boxes
below. Then hover the blue area above and leave the mouse there for 4
seconds. After the specified time, the box above should look exactly
like the second of the boxes below.</p>

<div>
	<span class="two">two</span>
	<span class="four">four</span>
	<span class="three">three</span>
	<span class="one">one</span>
</div>

<div>
	<span class="one">one</span>
	<span class="three">three</span>
	<span class="two">two</span>
	<span class="four">four</span>
</div>