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How to force light mode on regardless of theme

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  • Last reply by nick151

nick151
nick151
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I have a custom theme on Firefox called Charlies Red. Up until two days ago, Firefox would always consider it to be in light mode (which I prefer) whenever I'd use it. Now, however, it's in dark mode, and the only way I can return to light mode is to give up my custom theme and instead choose Light as a theme, which I don't like as much as Charlies Red.

Is there a way to force light mode on regardless of which theme I use? One source said I could go to about:config and create a ui.systemUsesDarkTheme number, setting it to 0, but I tried it to no avail and so deleted the number.

I have a custom theme on Firefox called Charlies Red. Up until two days ago, Firefox would always consider it to be in light mode (which I prefer) whenever I'd use it. Now, however, it's in dark mode, and the only way I can return to light mode is to give up my custom theme and instead choose Light as a theme, which I don't like as much as Charlies Red. Is there a way to force light mode on regardless of which theme I use? One source said I could go to about:config and create a ui.systemUsesDarkTheme number, setting it to 0, but I tried it to no avail and so deleted the number.

Chosen solution

You can change this pref on the about:config page from 3 to 2 to revert to the Firefox 94 behavior.

  • layout.css.prefers-color-scheme.content-override [dark:0, light:1, system:2, browser:3]

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

To go beyond that you need to use CSS code in userChrome.css.

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All Replies (2)

cor-el
cor-el
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Chosen Solution

You can change this pref on the about:config page from 3 to 2 to revert to the Firefox 94 behavior.

  • layout.css.prefers-color-scheme.content-override [dark:0, light:1, system:2, browser:3]

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

To go beyond that you need to use CSS code in userChrome.css.

nick151
nick151 Question owner
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cor-el said
You can change this pref on the about:config page from 3 to 2 to revert to the Firefox 94 behavior.
  • layout.css.prefers-color-scheme.content-override [dark:0, light:1, system:2, browser:3]
You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue. To go beyond that you need to use CSS code in userChrome.css.

That solved it! While changing the layout.css.prefers-color-scheme.content-override from 3 to 2 still kept Firefox in dark mode (which is strange, assuming 2 causes it to match Windows, which I have in light mode), the good news is that changing it to 1, which you said is light, fixed the problem instantly. Thank you!

Modified by nick151