Simple CSS only corner ribbon

ribbon.css

/*

Example:
https://share.cleanshot.com/yZOIpu

HTML: 
<div class="box">
  <div class="ribbon"><span>News</span></div>
</div>

*/

.box {
  position: relative;
  max-width: 600px;
  width: 90%;
  height: 400px;
  background: #fff;
}

.ribbon {
  width: 150px;
  height: 150px;
  overflow: hidden;
  position: absolute;
  top: 0;
  right: 0;
}

.ribbon span {
  position: absolute;
  display: block;
  width: 200px;
  padding: 5px 0;
  background-color: blue;
  color: #fff;
  text-transform: uppercase;
  text-align: center;
  font-size: 13px;
  font-weight: 800;
  left: 15px;
  top: 20px;
  transform: rotate(45deg);
}