<h1 class="cp_h1title">見出しテキスト</h1>

.cp_h1title {
  position: relative;
  color: #0097A7;
  background-color: #B2EBF2;
}
.cp_h1title::before,
.cp_h1title::after {
  position: absolute;
  content: '';
  background: #0097A7;
  display: block;
  width: 15px;
  height: 15px;
}
.cp_h1title::before {
  top: 100%;
  left: 0;
  clip-path: polygon(0 0, 100% 100%, 100% 0);
}
.cp_h1title::after {
  top: -15px;
  right: 0;
  clip-path: polygon(100% 100%, 0 100%, 0 0);
}