<h1 class="cp_h1title">見出しテキスト</h1>
.cp_h1title {
display: flex;
overflow: hidden;
background: #AB47BC;
padding: .3em;
align-items: center;
color:#ffffff;
}
.cp_h1title:before,.cp_h1title:after {
content: "";
flex: 1;
background: #fff;
padding: 1px 0;
height: 0;
transform: rotate(45deg);
}