GTK and Qt dark theme does not work.

[universish]

Description

settings > appearance > select gtk or qt theme and set dark theme, the theme is not dark, it is light. select classic theme and set dark theme, the theme is dark.

Also, when dark theme is set with Classic selected, the browser switches to dark theme. However, theme-compatible websites from the websites that are opened do not adjust their themes according to the theme of the browser or system. Their themes should automatically switch to dark theme, but they don't.

I use Fedora 40 OS

Steps to reproduce

1. Settings
2. Appearance
3. Select GTK or Qt or classic
4. Dark theme

Actual result

Themes not working

Expected result

Themes work.

Reproduces how often

Easily reproduced

Brave version (brave://version info)

v1.69.168

Channel information

• release (stable)
• beta
• nightly

Reproducibility

• with Brave Shields disabled
• with Brave Rewards disabled
• in the latest version of Chrome

Miscellaneous information

No response

[rebron]

cc: @fallaciousreasoning @aguscruiz @simonhong