<h1 class="cp_h1title">見出しテキスト</h1>
.cp_h1title {
position: relative;
padding: .3em;
}
.cp_h1title::before {
position: absolute;
left: 0;
content: '';
width: 100%;
height: 6px;
box-sizing: border-box;
bottom: 0;
border-top: 1px dotted #E91E63;
border-bottom: 2px solid #E91E63;
}