Chrome Stuck in Dark Mode After Switching System Theme (Linux)

Problem:

You switched your Linux system theme from dark to light, but Chrome is stuck in dark mode. Restarting Chrome doesn’t fix it.

Root Cause:

Chrome gets its theme preference from the XDG Desktop Portal via D-Bus. If you have multiple portal backends installed (e.g., xdg-desktop-portal-gtk and xdg-desktop-portal-gnome), the portal daemon may guess which to use. Chrome ends up listening to one backend while theme changes broadcast through another.

Solution:

Create a portal config that routes all requests through the GTK backend:

mkdir -p ~/.config/xdg-desktop-portal
echo -e "[preferred]\ndefault=gtk" > ~/.config/xdg-desktop-portal/portals.conf

Restart the portal service and fully quit Chrome (not just close the window—check the system tray):

systemctl --user restart xdg-desktop-portal

Relaunch Chrome. It should now respect your light theme.

Why This Works:

The GTK portal backend reads your theme preference from gsettings and emits D-Bus signals on changes. Forcing all portal requests through GTK ensures Chrome hears from a consistent source.

Verify:

dbus-send --session --dest=org.freedesktop.portal.Desktop --type=method_call --print-reply /org/freedesktop/portal/desktop org.freedesktop.portal.Settings.Read string:'org.freedesktop.appearance' string:'color-scheme'

Returns uint32 0 for light mode, uint32 1 for dark.

Back to the light. Carry on.