<h1 class="cp_h1title">見出しテキスト</h1>

.cp_h1title {
	position: relative;
	padding: .3em;
}
.cp_h1title::before,
.cp_h1title::after {
	content: '';
	position: absolute;
	bottom: -4px;
	left: 0;
	height: 4px;
}
.cp_h1title::before {
	z-index: 2;
	width: 15%;
	background-color: #E91E63;
}
.cp_h1title::after {
	width: 100%;
	background: repeating-linear-gradient(45deg, #fff, #fff 2px, #E91E63 2px, #E91E63 4px);
}