elk/styles/tiptap.css

.ProseMirror {
  p.is-editor-empty:first-child::before {
    content: attr(data-placeholder);
    float: left;
    pointer-events: none;
    height: 0;
    opacity: 0.4;
  }
  span[data-type='mention'],
  span[data-type='hashtag'] {
    --at-apply: text-primary;
  }
}