【見出し】ステッチラベル

<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>h2{
  width: 300px;
  height: 50px;
  line-height: 50px;
  padding: 0.5em;
  margin: 10px;
  color: #494949;
}

.midashi {
  position: relative;
  background: #142c5b;
  box-shadow: 0px 0px 0px 5px #142c5b;
  border: dashed 2px white;
  color: #FFF;
}

.midashi:after {
  position: absolute;
  content: '';
  left: -7px;
  top: -7px;
  border-width: 0 0 15px 15px;
  border-style: solid;
  border-color: #FFF #FFF #a8d4ff;
}</style>
</head>
<body>
<h2 class="midashi">ステッチラベルの見出し</h2>
<script>
</script>
</body>
</html>

h2{
  width: 300px;
  height: 50px;
  line-height: 50px;
  padding: 0.5em;
  margin: 10px;
  color: #494949;
}

.midashi {
  position: relative;
  background: #142c5b;
  box-shadow: 0px 0px 0px 5px #142c5b;
  border: dashed 2px white;
  color: #FFF;
}

.midashi:after {
  position: absolute;
  content: '';
  left: -7px;
  top: -7px;
  border-width: 0 0 15px 15px;
  border-style: solid;
  border-color: #FFF #FFF #a8d4ff;
}