Content styles

We distribute CKEditor 5 with two types of styles:

Editor styles for the editor’s user interface – see the Editor styles guide.
Content styles for the content inside the editor – covered in this guide.

If you went through our Quick start, you probably noticed that attaching the styles in JavaScript is pretty standard, and we provide CSS style sheets that have both the editor and content styles combined. There are separate styles for open-source and premium features:

import 'ckeditor5/ckeditor5.css';

import 'ckeditor5-premium-features/ckeditor5-premium-features.css';

It is as easy in HTML if you decide to use our CDN:

<link rel="stylesheet" href="https://cdn.ckeditor.com/ckeditor5/49.0.0/ckeditor5.css" />

<link rel="stylesheet" href="https://cdn.ckeditor.com/ckeditor5-premium-features/49.0.0/ckeditor5-premium-features.css" />

Why do I need content styles?

Some core editor features bring additional CSS to control the look of the content they produce. One such example is the image feature, which requires special content styles to render images and their captions within the content. Another would be the block quote feature that displays quotes in italics with a subtle border on the side. You can see both of these pictured below.

Editor content styles.

Customizing content styles

Content inside the editor is styled with native CSS variables, so you can adjust its look without touching the source styles.

Note

If the editor runs inside a shadow root, load the style sheets into that root and override the variables on the shadow host instead of :root. See the Shadow DOM guide for details.

General content styling

CKEditor 5 provides CSS variables to standardize font and line height styling across the content. These variables control the default appearance of text in the content. You can override them in the following way:

:root {
	/* Override the default font family */
	--ck-content-font-family: "Roboto";

	/* Override the default font size */
	--ck-content-font-size: 16px;

	/* Override the default font color */
	--ck-content-font-color: hsl(225, 5%, 45.00%);

	/* Override the default line height */
	--ck-content-line-height: 2;
}

Feature-specific styling

Individual features also provide CSS variables for their specific styling needs. For example, if you want to change the color of the mentions’ background and text, you can do the following override:

:root {
	--ck-content-color-mention-background: black;
	--ck-content-color-mention-text: white;
}

Note

Find the available CSS variables in our ckeditor5 and ckeditor5-premium-features packages.

Styling the published content

Your application is typically divided into two areas. Content creation, which hosts the editor and is a writing tool, and content publishing, which presents the written content.

It is important to use the content styles on the publishing side of your application. Otherwise, the content will look different in the editor and for your end users.

There are two ways to obtain the content styles:

From the npm packages, in the dist/ckeditor5-content.css and ckeditor5-premium-features-content.css location.
From our CDN, https://cdn.ckeditor.com/ckeditor5/

Below is an example with placeholder paths showing how to load the ckeditor5-content.css (and ckeditor5-premium-features-content.css, if needed) file on the publishing side.

<link rel="stylesheet" href="path/to/assets/ckeditor5-content.css">

<link rel="stylesheet" href="path/to/assets/ckeditor5-premium-features-content.css">

<link rel="stylesheet" href="path/to/assets/styles.css">

The final setup depends on how your application is structured. As mentioned earlier, you can use our CDN, or your JS bundler already creates and serves combined style sheets. Choose the solution that works best for your case.

Important

If you take a closer look at the content styles, you may notice they are prefixed with the .ck-content class selector. This narrows their scope when used in CKEditor 5 so they do not affect the rest of the application. To use them in the front–end, you will have to add the ck-content CSS class to the container of your content. Otherwise, the styles will not be applied.

Optimizing the size of style sheets

The ckeditor5 package distributes three style sheets:

ckeditor5.css – combined editor and content styles,
ckeditor5-content.css – only content styles,
ckeditor5-editor.css – only editor styles.

The same is true for the ckeditor5-premium-features package, but the filenames are different:

ckeditor5-premium-features.css – combined editor and content styles,
ckeditor5-premium-features-content.css – only content styles,
ckeditor5-premium-features-editor.css – only editor styles.

However, these style sheets include styles for all editor plugins. If you want to optimize the size of the style sheet, to only include styles for the plugins you use, you can follow the Optimizing build size guide.