<div class="cp_card">
コンテンツ
	<div class="cp_ribbon10">
		<span>Ribbon</span>
	</div>
</div>

.cp_card {
	width: 320px;
	height: 340px;
	position: relative;
	background: #ffffff;
	overflow: visible;
	margin: 2em auto;
	padding: 0.5em;
	border: 2px solid #9575CD;
	box-shadow: 0 0 5px rgba(0, 0, 0, 0.3);
}
.cp_ribbon10 {
	position: absolute;
	top: -6px;
	left: -6px;
	padding: 5px 10px;
	padding-right: 40px;
	letter-spacing: 0.1px;
	color: #ffffff;
	background: linear-gradient(-45deg,transparent,transparent 25%,#9575CD 0%,#9575CD);
}
.cp_ribbon10::before {
	position: absolute;
	z-index: 10;
	top: 100%;
	left: 0;
	content: ' ';
	border: 3px solid transparent;
	border-top: 3px solid #5E35B1;
	border-right: 3px solid #5E35B1;
}