Web/CSS/font-synthesis

The font-synthesis CSS property controls which missing typefaces, bold or italic, may be synthesized by the browser.

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Syntax

This property can take any one of the following forms:

The keyword value none.
Either of the keyword values weight and style.
Both the keyword values weight and style.

Values

none: Indicates that neither bold nor italic typeface may be synthesized.
weight: Indicates that a bold typeface may be synthesized if needed.
style: Indicates that an italic typeface may be synthesized if needed.

Description

Most standard Western fonts include italic and bold variants, but many novelty fonts do not. Fonts used for Chinese, Japanese, Korean and other logographic scripts tend not to include these variants, and synthesizing them may impede the legibility of the text. In these cases, it may be desirable to switch off the browser's default font-synthesis.

Formal definition

Initial value	`weight style`
Applies to	all elements. It also applies to `::first-letter` and `::first-line`.
Inherited	yes
Computed value	as specified
Animation type	discrete

Formal syntax

none | [ weight || style ]

Examples

Disabling font synthesis

HTML

<em class="syn">Synthesize me! 站直。</em>
<br/>
<em class="no-syn">Don't synthesize me! 站直。</em>

CSS

em {
  font-weight: bold;
}
.syn {
  font-synthesis: style weight;
}
.no-syn {
  font-synthesis: none;
}

Result

Specifications

Specification	Status	Comment
CSS Fonts Module Level 3The definition of 'font-synthesis' in that specification.	Candidate Recommendation	Initial definition

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`font-synthesis`	Chrome No support No	Edge No support No	Firefox Full support 34 Full support 34 No support 33 — 34 Disabled' Disabled' From version 33 until version 34 (exclusive): this feature is behind the `layout.css.font-features.enabled` preference (needs to be set to `true`). To change preferences in Firefox, visit about:config.	IE No support No	Opera No support No	Safari Full support 9	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 34	Opera Android No support No	Safari iOS Full support 9	Samsung Internet Android No support No

Legend

Full support: Full support
No support: No support
User must explicitly enable this feature.': User must explicitly enable this feature.