SOURCE

<h1>display:grid</h1>
<p>
主要属性：    <br>
grid-template-columns：//竖向排列<br>
grid-template-rows：//横向排列<br>
<br>
justify-self: center;<br>
align-self: center;
</p>
<br>
	<div class="content">
		<div class="b">1</div>
		<div class="b">2</div>
		<div class="b">3</div>
		<div class="b">4</div>
		<div class="b">5</div>
		<div class="b">6</div>
		<div class="b">7</div>
		<div class="b">8</div>
		<div class="b">9</div>
	</div>

.content {
    padding: 10px;
    display: grid;
    grid-template-columns: auto auto auto;
    grid-template-rows: auto auto auto;
    height: 780px;   
    background-color: #000;
    grid-gap: 10px;
}
.b {
    background-color: yellow;
}