JSFiddle - React, Tailwind, and code Playground
HTML
<div></div>
CSS
div {
position: relative;
width: 200px;
height: 280px;
border: 1px solid;
overflow: hidden;
}
div:before {
position: absolute;
top: 0;
left: 0;
width: 75%;
padding: 10px 0;
text-align: center;
color: #fff;
background: #f00;
content: 'nuevo';
-webkit-transform: translate(-25%, 50%) rotate(-45deg);
-moz-transform: translate(-25%, 50%) rotate(-45deg);
transform: translate(-25%, 50%) rotate(-45deg);
}