flex-direction (适用于父类容器的元素上)

.box{
	display:-webkit-flex;
	display:flex;
	margin:0;padding:10px;list-style:none;background-color:#eee;}
.box li{width:100px;height:100px;border:1px solid #aaa;text-align:center;}
#box{
	-webkit-flex-direction:row;
	flex-direction:row;
}
#box2{
	-webkit-flex-direction:row-reverse;
	flex-direction:row-reverse;
}
#box3{
	height:500px;
	-webkit-flex-direction:column;
	flex-direction:column;
}
#box4{
	height:500px;
	-webkit-flex-direction:column-reverse;
	flex-direction:column-reverse;
}

<h2>flex-direction:row</h2>
<ul id="box" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
</ul>
<h2>flex-direction:row-reverse</h2>
<ul id="box2" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
</ul>
<h2>flex-direction:column</h2>
<ul id="box3" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
</ul>
<h2>flex-direction:column-reverse</h2>
<ul id="box4" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
</ul>