<div>“The only way to get rid of a temptation is to yield to it.”
— Oscar Wilde, The Picture of Dorian Gray</div>

/**
 * Folded corner effect — at an angle
 */

div {
  margin: 20px auto;
	position: relative;
	width: 12em;
	background: #58a; /* Fallback */
	background: linear-gradient(-150deg, transparent 1.5em, #58a 0);
	padding: 2em;
	color: white;
	font: 100%/1.6 Baskerville, Palatino, serif;
	border-radius: .5em;
}

div::before {
	content: '';
	position: absolute;
	top: 0; right: 0;
	width: 1.73em; height: 3em;
	background: linear-gradient(to left bottom, transparent 50%, rgba(0,0,0,.2) 0, rgba(0,0,0,.4)) 100% 0 no-repeat;
	transform: translateY(-1.3em) rotate(-30deg);
	transform-origin: bottom right;
	border-bottom-left-radius: .5em;
	box-shadow: -.2em .2em .3em -.1em rgba(0,0,0,.15)
}