# \[Support\] Introducing Dark Website Forcer for Firefox 67

**URL:** <https://discourse.mozilla.org/t/support-introducing-dark-website-forcer-for-firefox-67/40628>\
**Category:** Add-on Support\
**Created:** [May 21, 2019, 9:16am UTC](https://discourse.mozilla.org/t/support-introducing-dark-website-forcer-for-firefox-67/40628 "2019-05-21T09:16:10Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![rugkx](https://sea1.discourse-cdn.com/flex001/user_avatar/discourse.mozilla.org/rugkx/32/19322_2.png) [@rugkx](https://discourse.mozilla.org/u/rugkx)\
**Post date:** [May 21, 2019, 9:16am UTC](https://discourse.mozilla.org/t/support-introducing-dark-website-forcer-for-firefox-67/40628/1 "2019-05-21T09:16:10Z")

</div>

## Background

Firefox 67 now supports the CSS media query [`prefers-color-scheme`](https://developer.mozilla.org/docs/Web/CSS/@media/prefers-color-scheme)!  
Website developers can use to adjust their website design to the (light or dark) system setting.  
Thus, they can support a “dark mode” or a “light mode” of their website.

## Get it

So here it is:  
**[Download Dark Website Forcer for Firefox  
  ![Firefox logo, Get the add-on](https://sea1.discourse-cdn.com/flex001/uploads/mozilla/original/3X/8/7/872b77dc0a098a05e086ee4063c1fd5f22798433.png)](https://addons.mozilla.org/de/firefox/addon/dark-mode-website-switcher/?src=external-mozdiscourse)**

([source code](https://github.com/rugk/website-dark-mode-switcher))

## Why add-on?

But I was missing an option to change that setting in my browser and make it independent of the rest of the system. (This may be useful for developing etc.)  
Also, the add-on makes it possible to use this dark mode on OSes that do not support any dark mode. (some Linux distros, Windows 7 etc.)

## Restrictions

However, I’ve had [some problems, and I have described that in the linked thread in detail](https://discourse.mozilla.org/t/can-extensions-overwrite-css-media-features-query/38606) when developing it. The TL;DR is: Mozilla Firefox does not have a proper API to toggle that setting or overwrite it for websites.

This means, there is one big restriction:

- It **cannot force a light style**! As most websites do not specify their light styling separately, but actually only add extra CSS for overwriting the light style.  
If [this bug is solved](https://bugzilla.mozilla.org/show_bug.cgi?id=1547818), this add-on could be much more flexible.