Codigo CSS para hacer un Post’it

.postit {
	line-height: 1;
	text-align:center;     
	width: 275px;    
	margin: 25px;    
	min-height:250px;
	max-height:250px;
	padding-top:35px;
	position:relative;   
	border:1px solid #E8E8E8;  
	border-top:60px solid #fdfd86;
	font-family:'Reenie Beanie';    
	font-size:22px;      
	border-bottom-right-radius: 60px 5px;
	display:inline-block;    
	background: #ffff88; /* Old browsers */
	background: -moz-linear-gradient(-45deg, #ffff88 81%, #ffff88 82%, #ffff88 82%, #ffffc6 100%); /* FF3.6+ */
	background: -webkit-gradient(linear, left top, right bottom, color-stop(81%,#ffff88), color-stop(82%,#ffff88), color-stop(82%,#ffff88), color-stop(100%,#ffffc6)); /* Chrome,Safari4+ */
	background: -webkit-linear-gradient(-45deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* Chrome10+,Safari5.1+ */
	background: -o-linear-gradient(-45deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* Opera 11.10+ */
	background: -ms-linear-gradient(-45deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* IE10+ */
	background: linear-gradient(135deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* W3C */
	filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ffff88', endColorstr='#ffffc6',GradientType=1 ); /* IE6-9 fallback on horizontal gradient */
}

.postit:after {     
   content: "";
  position:absolute;
  z-index:-1;
  right:-0px; bottom:20px;
  width:200px;
  height: 25px;
  background: rgba(0, 0, 0, 0.2);
  box-shadow:2px 15px 5px rgba(0, 0, 0, 0.40);
-moz-transform: matrix(-1, -0.1, 0, 1, 0, 0);
 -webkit-transform: matrix(-1, -0.1, 0, 1, 0, 0);
      -o-transform: matrix(-1, -0.1, 0, 1, 0, 0);
     -ms-transform: matrix(-1, -0.1, 0, 1, 0, 0);
         transform: matrix(-1, -0.1, 0, 1, 0, 0);
}

Para esta página:

.blog article.no-featured-content .archive-background,
.archive article.no-featured-content .archive-background,
article.type-jetpack-portfolio.no-featured-content .archive-background {
	height: 170px;
	background: #ffff88; /* Old browsers */
	background: -moz-linear-gradient(-45deg, #ffff88 81%, #ffff88 82%, #ffff88 82%, #ffffc6 100%); /* FF3.6+ */
	background: -webkit-gradient(linear, left top, right bottom, color-stop(81%,#ffff88), color-stop(82%,#ffff88), color-stop(82%,#ffff88), color-stop(100%,#ffffc6)); /* Chrome,Safari4+ */
	background: -webkit-linear-gradient(-45deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* Chrome10+,Safari5.1+ */
	background: -o-linear-gradient(-45deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* Opera 11.10+ */
	background: -ms-linear-gradient(-45deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* IE10+ */
	background: linear-gradient(135deg, #ffff88 81%,#ffff88 82%,#ffff88 82%,#ffffc6 100%); /* W3C */
	filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ffff88', endColorstr='#ffffc6',GradientType=1 ); /* IE6-9 fallback on horizontal gradient */ */
}