theme
=====

|  |  |
| --- | --- |
| Type | `Object` |
| Mandatory | No |
| Manifest version | 2 or higher |
| Example | 
```json
"theme": {
  "images": {
    "theme\_frame": "images/sun.jpg"
  },
  "colors": {
    "frame": "#CF723F",
    "tab\_background\_text": "#000"
  }
}
```
 |

Use the theme key to define a static theme to apply to Firefox.

**Note:** If you want to include a theme with an extension, please see the `theme` API.

**Note:** Since May 2019, themes need to be signed to be installed (Firefox bug 1545109). See Signing and distributing your add-on for more details.

**Note:** A new version of Firefox for Android, based on GeckoView, is under development. A pre-release version is available. The pre-release version does not support themes.

Image formats
-------------

The following image formats are supported in all theme image properties:

* JPEG
* PNG
* APNG
* SVG (animated SVG is supported from Firefox 59)
* GIF (animated GIF isn't supported)
Syntax
------

The theme key is an object that takes the following properties:

| Name | Type | Description |
| --- | --- | --- |
| `images` | `Object` | Optional as of Firefox 60. Mandatory before Firefox 60.

 A JSON object whose properties represent the images to display in
 various parts of the browser. See
 `images` for details on the
 properties that this object can contain.
  |
| `colors` | `Object` | Mandatory.

 A JSON object whose properties represent the colors of various parts
 of the browser. See `colors` for
 details on the properties that this object can contain.
  |
| `properties` | `Object` | Optional

 This object has properties that affect how the
 `"additional_backgrounds"` images are displayed and color schemes are applied. See
 `properties` for details on the properties that this object can contain.
  |

### images

All URLs are relative to the manifest.json file and cannot reference an external URL.

Images should be 200 pixels high to ensure they always fill the header space vertically.

| Name | Type | Description |
| --- | --- | --- |
| `theme_frame` | `String` | 
 The URL of a foreground image to be added to the header area and
 anchored to the upper right corner of the header area.


**Note:** Chrome anchors the image to the top left of
 the header and if the image doesn't fill the header area tile the
 image.


Optional in desktop Firefox 60 onwards. Required in Firefox for Android. |
| `additional_backgrounds` | `Array` of `String` | 

**Warning:** The
 `additional_backgrounds` property is experimental. It is
 currently accepted in release versions of Firefox, but its behavior
 is subject to change. It is not supported in Firefox for Android.


 An array of URLs for additional background images to be added to the
 header area and displayed behind the
 `"theme_frame":` image. These images layer the first image
 in the array on top, the last image in the array at the bottom.

Optional.

 By default all images are anchored to the upper right corner of the
 header area, but their alignment and repeat behavior can be controlled
 by properties of `"properties":`.
  |

### colors

These properties define the colors used for different parts of the browser. They are all optional. How these properties affect the Firefox UI is shown here:

|  |
| --- |
| 
Overview of the color properties and how they apply to Firefox UI components
 |

**Note:** Where a component is affected by multiple color properties, the properties are listed in order of precedence.

All these properties can be specified as either a string containing any valid CSS color string (including hexadecimal), or an RGB array, such as `"tab_background_text": [ 107 , 99 , 23 ]`.

**Note:** In Chrome, colors may only be specified as RGB arrays.

In Firefox for Android colors can be specified using:

* full hexadecimal notation, that is #RRGGBB only. *alpha* and shortened syntax, as in #RGB[A], are not supported.
* Functional notation (RGB arrays) for themes targeting Firefox 68.2 or later.

Colors for Firefox for Android themes cannot be specified using color names.


| Name | Description |
| --- | --- |
| `bookmark_text` | 
 The color of text and icons in the bookmark and find bars. Also, if
 `tab_text` isn't defined it sets the color of the active
 tab text and if `icons` isn't defined the color of the
 toolbar icons. Provided as Chrome compatible alias for
 `toolbar_text`.


**Note:** Ensure any color used contrasts well with
 those used in `frame` and `frame_inactive` or
 `toolbar` if you're using that property.


 Where `icons` isn't defined, also ensure good contrast
 with `button_background_active` and
 `button_background_hover`.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "tab\_background\_text": "white",
    "tab\_text": "white",
    "toolbar": "black",
    "bookmark\_text": "red"
  }
}
```

Browser Firefox is black. Browser's tab is black with white text. URL bar and the find in page bar are white with black text but all the browser and the find in page bar icons are red.
 |
| `button_background_active` | The color of the background of the pressed toolbar buttons.

See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "button\_background\_active": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are grey with white text. The customize toolbar icon in the url bar in white with a red background is pressed and a popup is open displaying a short list of thing to add to the toolbar such as the browser's library and the sidebars.
 |
| `button_background_hover` | The color of the background of the toolbar buttons on hover.

See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "button\_background\_hover": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are grey with white text. The go back one page icon is white with a red circle background.
 |
| `icons` | The color of toolbar icons, excluding those in the find toolbar.

**Note:** Ensure the color used contrasts well with
 those used in `frame`, `frame_inactive`,
 `button_background_active`, and
 `button_background_hover`.


See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "icons": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are grey with white text. The URL bar and open a new tab icons are red. The red icons contrast well with the black background color of the header area.
 |
| `icons_attention` | 
 The color of toolbar icons in attention state such as the starred
 bookmark icon or finished download icon.


**Note:** Ensure the color used contrasts well with
 those used in `frame`, `frame_inactive`,
 `button_background_active`, and
 `button_background_hover`.


See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "icons\_attention": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are grey with white text. The bookmark this page icon is red and pressed, an open popup name edit this bookmark is displayed. While in attention state, the toolbar icons contrast well with the black background of the header area.
 |
| `frame` | 
 The color of the header area background, displayed in the part of the
 header not covered or visible through the images specified in
 `"theme_frame"` and `"additional_backgrounds"`.


See example

```json
"theme": {
  "colors": {
     "frame": "red",
     "tab\_background\_text": "white"
  }
}
```

Browser firefox is red with white text. Browsers tabs are lighter red, also with white text. URL bar is very light red with black text
 |
| `frame_inactive` | 
 The color of the header area background when the browser window is
 inactive, displayed in the part of the header not covered or visible
 through the images specified in `"theme_frame"` and
 `"additional_backgrounds"`.


See example

```json
"theme": {
  "colors": {
     "frame": "red",
     "frame\_inactive": "gray",
     "tab\_text": "white"
  }
}
```

Browser firefox is grey. Browser's tabs and URL bar are lighter grey. The tab text is white and the URL bar icon are darker grey.
 |
| `ntp_background` | The new tab page background color.

See example

```json
"theme": {
  "colors": {
     "ntp\_background": "red"
  }
}
```

Firefox showing a new tab page. The background of the page is red.
 |
| `ntp_card_background` | The new tab page card background color.

See example

```json
"theme": {
  "colors": {
     "ntp\_card\_background": "red"
  }
}
```

Firefox showing a new tab page. On the page, the background to the search bar and shortcut buttons is red.
 |
| `ntp_text` | The new tab page text color.

**Note:** Ensure the color used contrasts well with
 that used in `ntp_background` and `ntp_card_background`.


See example

```json
"theme": {
  "colors": {
     "ntp\_text": "red"
  }
}
```

Firefox showing a new tab page. On the page, the text is in red.
 |
| `popup` | 
 The background color of popups (such as the URL bar dropdown and the
 arrow panels).


See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "popup": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are lighter grey with icons and text in white. The bookmark this page icon is blue and pressed, an open popup name 'edit this bookmark' is displayed with a red background. The background color of the popup is red.
 |
| `popup_border` | The border color of popups.

See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "popup": "black",
     "popup\_text": "white",
     "popup\_border": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are lighter grey with icons and text in white. The bookmark this page icon is blue and pressed, an open popup name 'edit this bookmark' is displayed with a red outline and black background. The popup's border is red.
 |
| `popup_highlight` | 
 The background color of items highlighted using the keyboard inside
 popups (such as the selected URL bar dropdown item).


**Note:** It's recommended to define
 `popup_highlight_text` to override the browser default
 text color on various platforms.


See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "popup\_highlight": "red",
     "popup\_highlight\_text": "white"
  }
}
```

screenshot of firefox is black. Browser's tabs and URL bar are lighter grey with icons and text in white. A search results popup is displayed with a highlighted item's background in red. The background color of the highlighted item inside the popup is red.
 |
| `popup_highlight_text` | The text color of items highlighted inside popups.

**Note:** Ensure the color used contrasts well with
 that used in `popup_highlight`.


See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "popup\_highlight": "black",
     "popup\_highlight\_text": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are lighter grey with icons and text in white. A search results popup is displayed with a highlighted item's text in red with a black background. The text color of the highlighted item contrasts well with the black background color of this item.
 |
| `popup_text` | The text color of popups.

**Note:** Ensure the color used contrasts well with
 that used in `popup`.


See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "popup": "black",
     "popup\_text": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are lighter grey with icons and text in white. A search results popup is displayed with items texts in red. The text color contrasts well with the black background color of the popup.
 |
| `sidebar` | The background color of the sidebar.

See example

```json
"theme": {
  "colors": {
     "sidebar": "red",
     "sidebar\_highlight": "white",
     "sidebar\_highlight\_text": "green",
     "sidebar\_text": "white"
  }
}
```

A close-up screenshot of a browser windows's open sidebar. The background color of the sidebar is red.
 |
| `sidebar_border` | The border and splitter color of the browser sidebar

See example

```json
"theme": {
  "colors": {
     "sidebar\_border": "red"
  }
}
```

A closeup of the firefox browser bookmarks sidebar with a red horizontal separator between the sidebar title and the sidebar menu. The border and splitter color of the sidebar is red.
 |
| `sidebar_highlight` | The background color of highlighted rows in built-in sidebars

See example

```json
"theme": {
  "colors": {
     "sidebar\_highlight": "red",
     "sidebar\_highlight\_text": "white"
  }
}
```

A closeup of the firefox browser bookmarks sidebar with a highlighted item. The background color of a highlighted row in the sidebar is red with white text.
 |
| `sidebar_highlight_text` | The text color of highlighted rows in sidebars.

**Note:** Ensure the color used contrasts well with
 that used in `sidebar_highlight`.


See example

```json
"theme": {
  "colors": {
    "sidebar\_highlight": "pink",
    "sidebar\_highlight\_text": "red",
  }
}
```

A closeup of the firefox browser bookmarks sidebar with a highlighted item. The color of the text of a highlighted row in the sidebar is red. The text color contrasts well with the pink background color of the highlighted row.
 |
| `sidebar_text` | The text color of sidebars.

**Note:** Ensure the color used contrasts well with
 that used in `sidebar`.


See example

```json
"theme": {
  "colors": {
     "sidebar": "red",
     "sidebar\_highlight": "white",
     "sidebar\_highlight\_text": "green",
     "sidebar\_text": "white"
  }
}
```

A close-up screenshot of a browser windows's open sidebar. The color of the text inside the sidebar is white. The text color contrasts well with the red background of the sidebar.
 |
| `tab_background_separator` 
Deprecated
 | 

**Warning:** `tab_background_separator` is
 not supported starting with Firefox 89.


The color of the vertical separator of the background tabs.

See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "tab\_background\_separator": "red"
  }
}
```

A closeup of browser tabs to highlight the separator.
 |
| `tab_background_text` | 
 The color of the text displayed in the inactive page tabs. If
 `tab_text` or `bookmark_text` isn't specified,
 applies to the active tab text.


**Note:** Ensure the color used contrasts well with
 those used in `tab_selected` or `frame` and
 `frame_inactive`.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "white",
    "tab\_background\_text": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tabs and URL bar are white with red icons and red text. The color of the text in the open tab is red. The text color contrasts well with the black background color of the tab.
 |
| `tab_line` | The color of the selected tab line.

See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "tab\_line": "red"
  }
}
```

Browser firefox is black. Browser's tabs and URL bar are darker grey with lighter grey icons and white text. The selected tab has a red outline.
 |
| `tab_loading` | The color of the tab loading indicator and the tab loading burst.

See example

```json
"theme": {
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "tab\_loading": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tabs and URL bar are darker grey with icons and text in white. Inside the selected tab an animated loading indicator is red.
 |
| `tab_selected` | 
 The background color of the selected tab. When not in use selected tab
 color is set by `frame` and the
 `frame_inactive`.


See example

```json
"theme": {
  "images": {
  "theme\_frame": "weta.png"
},
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "tab\_selected": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tabs and URL bar are darker grey with icons and text in white. The selected tab has red background and white text.
 |
| `tab_text` | 
 From Firefox 59, it represents the text color for the selected tab. If
 `tab_line` isn't specified, it also defines the color of
 the selected tab line.


**Note:** Ensure the color used contrasts well with
 those used in `tab_selected` or `frame` and
 `frame_inactive`.


See example

```json
"theme": {
  "images": {
  "theme\_frame": "weta.png"
},
  "colors": {
     "frame": "black",
     "tab\_background\_text": "white",
     "tab\_selected": "white",
     "tab\_text": "red"
  }
}
```

Browser firefox has a picture of an insect theme. URL bar is lighter grey with white icons. The selected tab text is red with white background.
 |
| `toolbar` | 
 The background color for the navigation bar, the bookmarks bar, and
 the selected tab.

This also sets the background color of the "Find" bar.

See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "red",
    "tab\_background\_text": "white"
  }
}
```

Browser firefox is black. Browser's tab, find in page bar and URL bar are red with white text and icons, except for the find in page bar where the text and icon are black.
 |
| `toolbar_bottom_separator` | 
 The color of the line separating the bottom of the toolbar from the
 region below.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "tab\_background\_text": "white",
    "toolbar\_bottom\_separator": "red"
  }
}
```

Browser firefox is black. Browser's tab and URL bar are lighter grey with white text and icons. A horizontal red line separates the bottom of the toolbar and the beginning of the display of the web page.
 |
| `toolbar_field` | The background color for fields in the toolbar, such as the URL bar.

 This also sets the background color of the
 **Find in page** field.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "tab\_background\_text": "white",
    "toolbar\_field": "red"
  }
}
```

Browser firefox is black. Browser's tab, find in page bar and URL bar are lighter grey with white text and icons. The background color of the URL bar is red. The find in page bar is white with black text. The find in page field is red with black text.
 |
| `toolbar_field_border` | The border color for fields in the toolbar.

 This also sets the border color of the
 **Find in page** field.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "black",
    "tab\_background\_text": "white",
    "toolbar\_field": "black",
    "toolbar\_field\_text": "white",
    "toolbar\_field\_border": "red"
  }
}
```

Browser firefox is black. Browser's tab, find in page and URL bar are black with white text and icons. The URL bar and find in page fields are outlined in red.
 |
| `toolbar_field_border_focus` | The focused border color for fields in the toolbar.

See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "black",
    "tab\_background\_text": "white",
    "toolbar\_field": "black",
    "toolbar\_field\_text": "white",
    "toolbar\_field\_border\_focus": "red"
  }
}
```

Browser firefox is black. Browser's tab and URL bar are black with white text and icons. The url bar field is focused and outlined in red.
 |
| `toolbar_field_focus` | 
 The focused background color for fields in the toolbar, such as the
 URL bar.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "black",
    "tab\_background\_text": "white",
    "toolbar\_field": "black",
    "toolbar\_field\_text": "white",
    "toolbar\_field\_focus": "red"
  }
}
```

Browser firefox is black. Browser's tab, find in page and URL bar are black with white text and icons. The background color of the focused URL bar is red and the text is white.
 |
| `toolbar_field_highlight` | 
 The background color used to indicate the current selection of text in
 the URL bar (and the search bar, if it's configured to be separate).

See example

```json
"theme": {
  "colors": {
    "toolbar\_field": "rgb(255 255 255 / 91%)",
    "toolbar\_field\_text": "rgb(0 100 0)",
    "toolbar\_field\_highlight": "rgb(180 240 180 / 90%)",
    "toolbar\_field\_highlight\_text": "rgb(0 80 0)"
  }
}
```

Browser firefox is white. Browser's tab and URL bar are white with text and icons in black. The URL bar field is focused and outlined in blue and URL bar text is selected.

 Here, the `toolbar_field_highlight` field specifies that
 the highlight color is a light green, while the text is set to a
 dark-to-medium green using `toolbar_field_highlight_text`.
  |
| `toolbar_field_highlight_text` | 
 The color used to draw text that's currently selected in the URL bar
 (and the search bar, if it's configured to be separate box).


**Note:** Ensure the color used contrasts well with
 those used in `toolbar_field_highlight`.


See example

```json
"theme": {
  "colors": {
    "toolbar\_field": "rgb(255 255 255 / 91%)",
    "toolbar\_field\_text": "rgb(0 100 0)",
    "toolbar\_field\_highlight": "rgb(180 240 180 / 90%)",
    "toolbar\_field\_highlight\_text": "rgb(0 80 0)"
  }
}
```

Browser firefox is white. Browser's tab and URL bar are white with text and icons in black. The URL bar field is focused and outlined in blue and URL bar text is selected.

 Here, the `toolbar_field_highlight_text` field is used to
 set the text color to a dark medium-dark green, while the highlight
 color is a light green.
  |
| `toolbar_field_separator` 
Deprecated
 | 

**Warning:** `toolbar_field_separator` is
 not supported starting with Firefox 89.


 The color of separators inside the URL bar. In Firefox 58 this was
 implemented as `toolbar_vertical_separator`.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "black",
    "tab\_background\_text": "white",
    "toolbar\_field\_separator": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser firefox is black. Browser's tab and URL bar are black with text and icons in white. Inside the white URL bar field, after the reader mode icon a red vertical line separating the rest of URL bar icons. The color of the vertical separator line inside the URL bar is red.

 In this screenshot, `"toolbar_vertical_separator"` is the
 red vertical line in the URL bar dividing the Reader Mode icon from
 the other icons.
  |
| `toolbar_field_text` | 
 The color of text in fields in the toolbar, such as the URL bar. This
 also sets the color of text in the
 **Find in page** field.


**Note:** Ensure the color used contrasts well with
 those used in `toolbar_field`.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "black",
    "tab\_background\_text": "white",
    "toolbar\_field": "black",
    "toolbar\_field\_text": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tab and URL bar are black with white text and icons. The text inside the URL bar is red. The icons and find in page field have red text with black background.
 |
| `toolbar_field_text_focus` | 
 The color of text in focused fields in the toolbar, such as the URL
 bar.


**Note:** Ensure the color used contrasts well with
 those used in `toolbar_field_focus`.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "toolbar": "black",
    "tab\_background\_text": "white",
    "toolbar\_field": "black",
    "toolbar\_field\_text": "white",
    "toolbar\_field\_text\_focus": "red"
  }
}
```

A screenshot of a browser window with two open tabs. Browser is black. Browser's tab and URL bar are black with text and icons in white. The URL bar has focus; the bar's text and icons are red with black background.
 |
| `toolbar_text` | 
 The color of toolbar text. This also sets the color of text in the
 "Find" bar.


**Note:** For compatibility with Chrome, use the alias
 `bookmark_text`.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "tab\_background\_text": "white",
    "toolbar": "black",
    "toolbar\_text": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tab, find in page bar, and URL bar are black with red text and icons. The text inside the active tab, the navigator bar and the find bar is red.
 |
| `toolbar_top_separator` | 
 The color of the line separating the top of the toolbar from the
 region above.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "tab\_background\_text": "white",
    "toolbar": "black",
    "toolbar\_top\_separator": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tab and URL bar are black with white text and icons. A red line separates the top of the URL bar from the browser.
 |
| `toolbar_vertical_separator` | 
 The color of the separator in the bookmarks toolbar. In Firefox 58, it
 corresponds to the color of separators inside the URL bar.


See example

```json
"theme": {
  "colors": {
    "frame": "black",
    "tab\_background\_text": "white",
    "toolbar": "black",
    "toolbar\_vertical\_separator": "red"
  }
}
```

A screenshot of a browser window with one open tab. Browser is black. Browser's tab and URL bar are black with text and icons in white. The color of the vertical line separating the bookmarks toolbar from the content to the right is red.
 |

#### Aliases

Additionally, this key accepts various properties that are aliases for one of the properties above. These are provided for compatibility with Chrome. If an alias is given, and the non-alias version is also given, then the value will be taken from the non-alias version.

| Name | Alias for |
| --- | --- |
| `bookmark_text` | `toolbar_text` |

### properties

| Name | Type | Description |
| --- | --- | --- |
| `additional_backgrounds_alignment` | `Array` of `String` | Optional

 An array of enumeration values defining the alignment of the
 corresponding `"additional_backgrounds":` array item.The
 alignment options include:
 * `"bottom"`
* `"center"`
* `"left"`
* `"right"`
* `"top"`
* `"center bottom"`
* `"center center"`
* `"center top"`
* `"left bottom"`
* `"left center"`
* `"left top"`
* `"right bottom"`
* `"right center"`
* `"right top"`.

If not specified, defaults to `"right top"`. |
| `additional_backgrounds_tiling` | `Array` of `String` | Optional

 An array of enumeration values defining how the corresponding
 `"additional_backgrounds":` array item repeats. Options
 include:
 * `"no-repeat"`
* `"repeat"`
* `"repeat-x"`
* `"repeat-y"`

If not specified, defaults to `"no-repeat"`. |
| `color_scheme` | `String` | Optional

 Determines which color scheme is applied to the chrome (for example, context menus)
 and content (for example, built-in pages and the preferred color scheme for web pages).
 Options include:
 * `"auto"` – a light or dark scheme based automatically on the theme.
* `"light"` – a light scheme.
* `"dark"` – a dark scheme.
* `"system"` – uses the system scheme.

If not specified, defaults to `"auto"`. |
| `content_color_scheme` | `String` | Optional

 Determines which color scheme is applied to the content (for example, built-in pages and
 preferred color scheme for web pages). Overrides `color_scheme`. Options
 include:
 * `"auto"` – a light or dark scheme based automatically on the theme.
* `"light"` – a light scheme.
* `"dark"` – a dark scheme.
* `"system"` – the system scheme.

If not specified, defaults to `"auto"`. |

Examples
--------

A basic theme must define an image to add to the header, the accent color to use in the header, and the color of text used in the header:


```json
 "theme": {
   "images": {
     "theme\_frame": "images/sun.jpg"
   },
   "colors": {
     "frame": "#CF723F",
     "tab\_background\_text": "#000"
   }
 }
```


Multiple images can be used to fill the header. Before Firefox version 60, use a blank or transparent header image to gain control over the placement of each additional image:


```json
 "theme": {
   "images": {
     "additional\_backgrounds": [ "images/left.png", "images/middle.png", "images/right.png"]
   },
   "properties": {
     "additional\_backgrounds\_alignment": [ "left top", "top", "right top"]
   },
   "colors": {
     "frame": "blue",
     "tab\_background\_text": "#ffffff"
   }
 }
```


You can also fill the header with a repeated image, or images, in this case a single image anchored in the middle top of the header and repeated across the rest of the header:


```json
 "theme": {
   "images": {
     "additional\_backgrounds": [ "images/logo.png"]
   },
   "properties": {
     "additional\_backgrounds\_alignment": [ "top" ],
     "additional\_backgrounds\_tiling": [ "repeat"  ]
   },
   "colors": {
     "frame": "green",
     "tab\_background\_text": "#000"
   }
 }
```


The following example uses most of the different values for `theme.colors`:


```json
  "theme": {
    "images": {
      "theme\_frame": "weta.png"
    },

    "colors": {
       "frame": "darkgreen",
       "tab\_background\_text": "white",
       "toolbar": "blue",
       "bookmark\_text": "cyan",
       "toolbar\_field": "orange",
       "toolbar\_field\_border": "white",
       "toolbar\_field\_text": "green",
       "toolbar\_top\_separator": "red",
       "toolbar\_bottom\_separator": "white",
       "toolbar\_vertical\_separator": "white"
    }
  }
```


It will give you a browser that looks like this:

![A browser window with two open tabs and dark green background color in the header area. The inactive tab has a white text color. The active tab and the toolbar have a blue background color with cyan-colored text. The URL bar has an orange background with white borders, a green text color and a white-colored vertical line separator. A red-colored line is used to separate the tabs on the top and a white line to separate the tabs from the content bellow them.](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme/theme.png)

In this screenshot, `"toolbar_vertical_separator"` is the white vertical line in the URL bar dividing the Reader Mode icon from the other icons.

Browser compatibility
---------------------

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

### Chrome compatibility

In Chrome:

* `colors/toolbar_text` is not used, use `colors/bookmark_text` instead.
* `images/theme_frame` anchors the image to the top left of the header and if the image doesn't fill the header area tile the image.
* all colors must be specified as an array of RGB values, like this:

```json
"theme": {
  "colors": {
     "frame": [255, 0, 0],
     "tab\_background\_text": [0, 255, 0],
     "bookmark\_text": [0, 0, 255]
  }
}
```

From Firefox 59 onward, both the array form and the CSS color form are accepted for all properties. Before that, `colors/frame` and `colors/tab_background_text` required the array form, while other properties required the CSS color form.