light-dark()

The light-dark() CSS <color> function enables setting two colors for a property - returning one of the two colors options by detecting if the developer has set a light or dark color scheme or the user has requested light or dark color theme - without needing to encase the theme colors within a prefers-color-scheme media feature query. Users are able to indicate their color-scheme preference through their operating system settings (e.g. light or dark mode) or their user agent settings. The light-dark() function enables providing two color values where any <color> value is accepted. The light-dark() CSS color function returns the first value if the user's preference is set to light or if no preference is set and the second value if the user's preference is set to dark.

To enable support for the light-dark() color function, the color-scheme must have a value of light dark, usually set on the :root pseudo-class.

css
:root {
  color-scheme: light dark;
}
body {
  color: light-dark(#333b3c, #efefec);
  background-color: light-dark(#efedea, #223a2c);
}

Syntax

css
/* Named color values */
color: light-dark(black, white);

/* RGB color values */
color: light-dark(rgb(0 0 0), rgb(255 255 255));

/* Custom properties */
color: light-dark(var(--light), var(--dark));

Values

Functional notation: light-dark(light-color, dark-color)

light-color

<color> value to be set for light color-scheme.

dark-color

<color> value to be set for dark color-scheme.

Formal syntax

<light-dark()> = 
light-dark( <color> , <color> )

Example

Setting colors based on color scheme

By default, in supporting browsers, the color returned by the light-dark() color function depends on the user preference set through an operating system's settings (e.g., light or dark mode) or from a user agent setting. You can also change this setting in the browser's developer tools.

HTML

We include three sections to enable targeting light colors, dark colors, and the colors selected based on the user's preferred color scheme.

html
<h1><code>light-dark()</code> CSS function</h1>
<section>
  <h2>Automatic</h2>
  <p>This section will react to the users system or user agent setting.</p>
</section>
<section class="light">
  <h2>Light</h2>
  <p>
    This section will be light due to the <code>color-scheme: light;</code>.
  </p>
</section>
<section class="dark">
  <h2>Dark</h2>
  <p>This section will be dark due to the <code>color-scheme: dark;</code>.</p>
</section>

CSS

We include colors for both light and dark themes. We also define color-scheme for the document on the :root to enable the light-dark() color function for the entire document.

css
:root {
  /* this has to be set to switch between light or dark */
  color-scheme: light dark;

  --light-bg: ghostwhite;
  --light-color: darkslategray;
  --light-code: tomato;

  --dark-bg: darkslategray;
  --dark-color: ghostwhite;
  --dark-code: gold;
}
* {
  background-color: light-dark(var(--light-bg), var(--dark-bg));
  color: light-dark(var(--light-color), var(--dark-color));
}
code {
  color: light-dark(var(--light-code), var(--dark-code));
}

In addition to enabling the light-dark() function, the color-scheme property enables overriding a user's color scheme for document sections. Forcing a page section to only use a light or dark color scheme can be done by setting the color-scheme property to light or dark.

Note: Generally this should not be done, we are using it here for demonstration purposes. If the user has made a preference, you generally should not override their preferences.

css
.light {
  /* forces light color-scheme */
  color-scheme: light;
}
.dark {
  /* forces dark color-scheme */
  color-scheme: dark;
}

Result

Specifications

Specification
CSS Color Module Level 5
# light-dark

Browser compatibility

BCD tables only load in the browser

See also