CodePen Embed - 區塊水平置中 margin: auto

<body>
	<div class="section-h-middle"></div>
</body>

/* 水平置中 */
.section-h-middle {
	width: 50%;
	height: 200px;
	margin: 10px auto;
	
	/* 好看用 */
	border: 1px solid #000;
}

This Pen is owned by Ted Liou on CodePen.

This Pen doesn't use any external CSS resources.

This Pen doesn't use any external JavaScript resources.