<h1 class="cp_h1title">見出しテキスト</h1>
.cp_h1title {
position: relative;
padding: .3em;
border: solid 2px #2196F3;
border-radius: 3px 0 3px 0;
}
.cp_h1title:before,.cp_h1title:after {
content: '';
position: absolute;
width:10px;
height: 10px;
border: solid 2px #2196F3;
border-radius: 50%;
}
.cp_h1title:after {
bottom: 100%;
right: 100%;
}
.cp_h1title:before {
top: 100%;
left: 100%;
}