<div class="cp_card">
コンテンツ
	<div class="cp_ribbon11">
		<span>Ribbon</span>
	</div>
</div>

.cp_card {
	width: 320px;
	height: 340px;
	position: relative;
	background: #ffffff;
	overflow: visible;
	margin: 2em auto;
	padding: 0.5em;
	box-shadow: 0 0 5px rgba(0, 0, 0, 0.3);
}
.cp_ribbon11 {
	line-height: 50px;
	position: absolute;
	top: 15px;
	display: block;
	width: calc(100% + 20px);
	height: 50px;
	margin-right: -10px;
	margin-left: -18px;
	text-align: center;
	color: #ffffff;
	background: #2196F3;
}
.cp_ribbon11:before, .cp_ribbon11:after {
	position: absolute;
	content: '';
}
.cp_ribbon11:before {
	bottom: -10px;
	left: 0;
	width: 0;
	height: 0;
	border-top: 10px solid #1565C0;
	border-left: 10px solid transparent;
}
.cp_ribbon11:after {
	right: 0;
	bottom: -10px;
	width: 0;
	height: 0;
	border-top: 10px solid #1565C0;
	border-right: 10px solid transparent;
}