@ckeditor/ckeditor5-engine/theme/renderer.css

The editing engine of CKEditor 5 – the best browser-based rich text editor.

/*
 * Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */

/* Elements marked by the Renderer as hidden should be invisible in the editor. */
.ck.ck-editor__editable span[data-ck-unsafe-element] {
	display: none;
}