<h1 class="cp_h1title">見出しテキスト</h1>

.cp_h1title {
  position: relative;
  color: #ffffff;
  background: #311b92;/*見出しの色*/
  background-image:/*見出しの背景*/
    linear-gradient( 45deg, rgba(69,39,160 ,1) 25%, transparent 25%, transparent 75%, rgba(69,39,160 ,1) 75%, rgba(69,39,160 ,1)),
    linear-gradient( -45deg, rgba(69,39,160 ,1) 25%, transparent 25%, transparent 75%, rgba(69,39,160 ,1) 75%, rgba(69,39,160 ,1));
  background-position: 0 0, 10px 10px;
  background-size: 20px 20px;
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.6);
  padding: 5px 10px;
}
.cp_h1title::before,
.cp_h1title::after {
  position: absolute;
  content: '';
  width: 0;
  height: 60px;/*ラインの長さ*/
  border: solid #9c27b0;/*ラインの太さ・形状・色*/
  border-width: 0 0 0 1px;
  transform: rotate(45deg);/*ラインの傾き*/
}
.cp_h1title::before {/*左のライン位置*/
  top: -20px;
  left: 10px;
}
.cp_h1title::after {/*右のライン位置*/
  bottom: -20px;
  right: 10px;
}