<style>
	.demo_css_sprt, .demo_css_sprt div	{
		border: dotted 1px red;
		padding:1em;
	}
	.demo_css_sprt div	{
		margin: 1em 0;
	}
	.demo_css_sprt p	{
		border: dashed 1px blue;
		padding:1em;
	}
	.demo_css_sprt div:nth-child(2)	{
		background: mistyrose;
	}
</style>
<div class="demo_css_sprt">
	要素1
	<div>
	要素2
		<div>要素3</div>
		<div>要素4</div>
		<div>要素5</div>
		<div>要素6</div>
	</div>
	<p>要素7</p>
	<div>
		要素8
		<p>要素9</p>
		<div>要素10</div>
		<p>要素11</p>
		<div>要素12</div>
		<p>要素13</p>
	</div>
	<div>要素14</div>
</div>