Edit in JSFiddle

<div id="ribbon">
    <div class="container">
        <div class="base"></div>
        <div class="top_corner"></div>
        <div class="bottom_corner"></div>
    </div>
</div>

body {
  margin: 0;
  padding: 0;
}

#ribbon {
  width: 280px;
  height: 180px;
  margin: 30px 0 0;
  position: relative;
  overflow: hidden;
}

/* top and bottom border of ribbon */
#ribbon .container {
  position: relative;
  width: 250px;
  height: 100px;
  overflow: hidden;
  margin: 0;
  border-top: 1px solid #631a15;
  border-bottom: 1px solid #631a15;
}

#ribbon .base {
  width: 200px;
  height: 100px;
  position: relative;
  z-index: 2;
  /* generated in colorzilla, http://www.colorzilla.com/gradient-editor/ */
  background: #c73b3c; /* Old browsers */
  background: -moz-linear-gradient(left, #c73b3c 0%, #b8201f 100%); /* FF3.6+ */
  background: -webkit-gradient(linear, left top, right top, color-stop(0%,#c73b3c), color-stop(100%,#b8201f)); /* Chrome,Safari4+ */
  background: -webkit-linear-gradient(left, #c73b3c 0%,#b8201f 100%); /* Chrome10+,Safari5.1+ */
  background: -o-linear-gradient(left, #c73b3c 0%,#b8201f 100%); /* Opera 11.10+ */
  background: -ms-linear-gradient(left, #c73b3c 0%,#b8201f 100%); /* IE10+ */
  background: linear-gradient(to right, #c73b3c 0%,#b8201f 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#c73b3c', endColorstr='#b8201f',GradientType=1 ); /* IE6-9 */
}

/* Add dashed line (stitches) on top and bottom of ribbon */
#ribbon .base:after {
  content: '';
  position: absolute;
  top: 6px;
  width: 242px;
  height: 86px;
  border-top: 1px dashed #631a15;
  border-bottom: 1px dashed #631a15;
}

#ribbon .top_corner {
 width: 100px;
 height: 100px;
 background: #b8201f;
 position: absolute;
 z-index: 1;
 bottom: 60px;
 left: 140px;
 -webkit-transform: rotate(45deg);
 -moz-transform: rotate(45deg);
 -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}

#ribbon .bottom_corner {
	width: 100px;
	height: 100px;
	background: #b8201f;
	position: absolute;
	bottom: -60px;
	right: 10px;
	z-index: 1;
	
	-webkit-transform: rotate(45deg);
	-moz-transform: rotate(45deg);
	-ms-transform: rotate(45deg);
	-o-transform: rotate(45deg);
	transform: rotate(45deg);
}