div#page::before { z-index:9999; position:absolute; content: 'NO 41-bis'; font-family: Helvetica; font-weight: bolder; font-size: 1.4em; width: 200px; text-align: center; line-height: 50px; letter-spacing: 1px; color: red; transform: rotate(-45deg); -webkit-transform: rotate(-45deg); position: fixed; box-shadow: 0 0 10px rgba(0,0,0,.3); top: 25px; right: -50px; transform: rotate(45deg); -webkit-transform: rotate(45deg); background: #FFF; z-index: 9999; }
You have to write this in ASPETTO > PERSONALIZZA > CUSTOM CSS