align-content (适用于父类容器上)

.box{
	display:-webkit-flex;
	display:flex;
	-webkit-flex-wrap:wrap;
	flex-direction:wrap;
	width:200px;height:200px;margin:0;padding:0;border-radius:5px;list-style:none;background-color:#eee;}
.box li{margin:5px;padding:10px;border-radius:5px;background:#aaa;text-align:center;}
#box{
	-webkit-align-content:flex-start;
	align-content:flex-start;
}
#box2{
	-webkit-align-content:flex-end;
	align-content:flex-end;
}
#box3{
	-webkit-align-content:center;
	align-content:center;
}
#box4{
	-webkit-align-content:space-between;
	align-content:space-between;
}
#box5{
	-webkit-align-content:space-around;
	align-content:space-around;
}
#box6{
	-webkit-align-content:strecth;
	align-content:strecth;
}

<h2>align-content:flex-start</h2>
<ul id="box" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
	<li>d</li>
	<li>e</li>
	<li>f</li>
</ul>
<h2>align-content:flex-end</h2>
<ul id="box2" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
	<li>d</li>
	<li>e</li>
	<li>f</li>
</ul>
<h2>align-content:center</h2>
<ul id="box3" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
	<li>d</li>
	<li>e</li>
	<li>f</li>
</ul>
<h2>align-content:space-between</h2>
<ul id="box4" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
	<li>d</li>
	<li>e</li>
	<li>f</li>
</ul>
<h2>align-content:space-around</h2>
<ul id="box5" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
	<li>d</li>
	<li>e</li>
	<li>f</li>
</ul>
<h2>align-content:strecth</h2>
<ul id="box6" class="box">
	<li>a</li>
	<li>b</li>
	<li>c</li>
	<li>d</li>
	<li>e</li>
	<li>f</li>
</ul>