[data-type="core/code"] {
  background: rgba(255, 0, 0, .10);
}

[data-type="tilleuls/code"] .wp-block-code {
  position: relative;
}

[data-type="tilleuls/code"] .wp-block-code:before {
  content: attr(data-language);
  position: absolute;
  top: 0;
  right: 0;
  padding: 2px 3px;
  background: #444;
  color: #fefefe;
  font-size: .8rem;
}