bug#52475: [Question] About CSS prefers-color-scheme render in icecat

[Mark H Weaver]

tags 52475 notabug
close 52475
thanks

Hi,

morisum via bug-gnuzilla via GNUzilla bug reports 
writes:

> I tried to use icecat with dark mode; however, the website page won't
> automatically change to dark mode as expected. To be more specific the
> "prefers-color-scheme:dark" in CSS
> (https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-color-scheme).

It doesn't work because in IceCat the "privacy.resistFingerprinting"
option in  is set to "true" by default.  If you set it to
"false", scripts will then be able to determine your preferred color
scheme, local time zone, and several other pieces of information.

It would be nice to allow finer-grained control over which pieces of
information to allow scripts to see.  Mozilla opted for a single boolean
switch.  I would welcome patches to improve this situation.

 Regards,
   Mark

-- 
Disinformation flourishes because many people care deeply about injustice
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bug#52475: [Question] About CSS prefers-color-scheme render in icecat

[morisum via bug-gnuzilla via GNUzilla bug reports]

Hi all,

I tried to use icecat with dark mode; however, the website page won't 
automatically change to dark mode as expected. To be more specific the 
"prefers-color-scheme:dark" in CSS 
(https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-color-scheme). 
I tried multiple versions on multiple distros to recreate test this; however, 
none of it works.

Here is a list of all the test I did:

guix (icecat 78.10.0-guix0-preview1)

guix (icecat 91.4.0-guix0-preview1)

parabola (78.10.0_pre2-1)

arch (91.40 compiled from source)

arch (78.10 compiled from aur)

ubuntu20.04 (install from https://gnu.freemirror.org/gnu/gnuzilla/60.7.0/)

I tried to use the system dark mode settings (for example, in ubuntu), or the 
adwaita-dark theme, as well as to config the gtk3 directly under 
~/.config/gtk-3.0/settings.ini with gtk-application-prefer-dark-theme=1 or 
gtk-application-prefer-dark-theme=true. I also tried to set 
ui.systemUsesDarkTheme=1 and other settings in the about:config. But none of 
those behave as expected.

All the distros are freshly installed; you can use the official qemu image from 
arch 
(https://gitlab.archlinux.org/archlinux/arch-boxes/-/jobs/41421/artifacts/file/output/Arch-Linux-x86_64-basic-20211212.41421.qcow2)
 or guix 
(https://ftp.gnu.org/gnu/guix/guix-system-vm-image-1.3.0.x86_64-linux.qcow2) to 
recreate this situation.

I think this might be a missing feature? Can someone check what the problem is? 
Would you please let me know if there is anything else I need to provide?
Thanks in advance!

morisum