Ruban pour promouvoir un livre

corner-ribbon.css

@import url('//fonts.googleapis.com/css?family=Tangerine');

/* The ribbons */
.corner-ribbon {
  font-family: "Tangerine",sans-serif;
  width: 400px;
  background: #e43;
  position: absolute;
  top: 50px;
  left: -100px;
  text-align: center;
  line-height: 45px;
  letter-spacing: 0em;
  color: white;
  transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
}

.corner-ribbon a {
  text-decoration: none;
  font-style: italic;
  color: white;
  font-size: 200%;
}

/* Custom styles */

.corner-ribbon.sticky {
  position: fixed;
}

.corner-ribbon.shadow{
  box-shadow: 0 0 3px rgba(0,0,0,.3);
}

/* Different positions */
.corner-ribbon.top-left{
  top: 50px;
  left: -100px;
  transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
}

.corner-ribbon.top-right{
  top: 50px;
  right: -100px;
  left: auto;
  transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
}

.corner-ribbon.bottom-left{
  top: auto;
  bottom: 50px;
  left: -100px;
  transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
}

.corner-ribbon.bottom-right{
  top: auto;
  right: -100px;
  bottom: 50px;
  left: auto;
  transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
}

/* Colors */
.corner-ribbon.white{background: #f0f0f0; color: #555;}
.corner-ribbon.black{background: #333;}
.corner-ribbon.grey{background: #999;}
.corner-ribbon.blue{background: #39d;}
.corner-ribbon.green{background: #2c7;}
.corner-ribbon.turquoise{background: #1b9;}
.corner-ribbon.purple{background: #95b;}
.corner-ribbon.red{background: #e43;}
.corner-ribbon.orange{background: #e82;}
.corner-ribbon.yellow{background: #ec0;}
.corner-ribbon.gold{background: #C4A451;}

snippet.html

<div class="corner-ribbon sticky gold shadow"><a href="http://www.editions-vendemiaire.com/catalogue/a-paraitre/kaamelott-un-livre-d-histoire-florian-besson-et-justine-breton-dir/">Un tout nouveau<br> livre sur Kaamelott !</a></div>