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<h1 class="title4">
WEBデザイナーのしおり
</h1>

.title4 {
	position: relative;
	padding: .75em 1em .75em 1.5em;
	border: 1px solid #ccc;
}
.title4::after {
	position: absolute;
	top: .5em;
	left: .5em;
	content: '';
	width: 6px;
	height: -webkit-calc(100% - 1em);
	height: calc(100% - 1em);
	background-color: #3498db;
	border-radius: 4px;
}