<ol class="cp_clist">
	<li>css</li>
	<li>html</li>
	<li>copy</li>
	<li>easy</li>
</ol>

ol.cp_clist {
	counter-reset:cp_clist; /*数字をリセット*/
	list-style-type: none;
	padding:0.5em;
}
ol.cp_clist li {
	position: relative;
	padding-left: 30px;
	line-height: 1.5em;
	padding: 0.5em 0.5em 0.5em 36px;
}
ol.cp_clist li::before {
	position: absolute;
	display:inline-block;
	top: 50%;
	left: 0;
	/* カウントさせる */
	counter-increment: cp_clist;
	content: counter(cp_clist);
	/*装飾*/
	padding: 0 0.2em 0 0.2em;
	background: #03A9F4;
	color: #fff;
	font-weight:bold;
	font-size: 15px;
	border-radius: 50%;
	width: 25px;
	height: 25px;
	line-height: 25px;
	text-align:center;
	transform: translateY(-50%);
}
ol.cp_clist li::after {
	position: absolute;
	content: '';
	display: block;
	top: 50%;
	left: 18px;
	height: 0;
	width: 0;
	border-top: 7px solid transparent;
	border-bottom: 7px solid transparent;
	border-left: 12px solid #03A9F4;
	transform: translateY(-50%);
}