Ok, so I am here again with my problem. Can't change Lutris theme to dark mode

Support
1

So, this is my previous post:

I had Lutris in dark mode when I downloaded it. But 2 weeks ago, I changed the themes from default to:

Applications: Mint-x
Icons: Mint-X-Yellow
Desktop/panel: cinnamon

obrázok

Now, when I am trying to change Lutris to dark mode, it has no effect, it is still in light mode.

I also tried this tutorial, but it didn’t worked. I installed flatseal, added one line “filesystem” section, where I typed ~/.themes. And before it, I typed sudo flatpak override --filesystem=$HOME/.themes in terminal. But I forgot that I don’t have any theme in ~/.theme folder, so I changed that line to /usr/share/themes.
Then I created another line, now in “environment” section and typed GTK_THEME=Mint-L-Dark, but still didn’t work.
I don’t know what I did wrong. Can you help me please?

Here, I am adding more info:

Lutris logs:

[INFO:2025-07-28 16:15:42,928:application]: Starting Lutris 0.5.19
[INFO:2025-07-28 16:15:42,951:startup]: “card1” is Intel Iris Xe Graphics (8086:46a6 1043:277d i915) Driver 25.0.7
[INFO:2025-07-28 16:15:43,085:startup]: “card2” is NVIDIA GeForce RTX 4060 Laptop GPU (10de:28e0 1043:277d nvidia) Driver 550.163.01
[DEBUG:2025-07-28 16:15:43,170:xrandr]: Retrieving resolution list
[DEBUG:2025-07-28 16:15:43,205:xrandr]: Retrieving 59 video modes from XrandR
[DEBUG:2025-07-28 16:15:43,242:path_cache]: Checking for missing games
[DEBUG:2025-07-28 16:15:43,266:api]: Modified at Po 28. júl 2025, 16:06:41, will update after Po 28. júl 2025, 22:06:41
[DEBUG:2025-07-28 16:15:43,267:lutriswindow]: Runtime up to date
[DEBUG:2025-07-28 16:15:44,245:http]: POST https://lutris.net/api/users/library?since=1753711602
[DEBUG:2025-07-28 16:16:32,507:xrandr]: Retrieving display outputs
[DEBUG:2025-07-28 16:16:34,081:xrandr]: Retrieving 59 video modes from XrandR
[DEBUG:2025-07-28 16:16:34,083:xrandr]: Retrieving display outputs
[DEBUG:2025-07-28 16:16:34,112:xrandr]: Retrieving 59 video modes from XrandR
[DEBUG:2025-07-28 16:16:34,114:xrandr]: Retrieving resolution list
[DEBUG:2025-07-28 16:16:34,146:xrandr]: Retrieving 59 video modes from XrandR
[DEBUG:2025-07-28 16:16:34,151:xrandr]: Retrieving resolution list
[DEBUG:2025-07-28 16:16:34,179:xrandr]: Retrieving 59 video modes from XrandR
[DEBUG:2025-07-28 16:16:34,182:xrandr]: Retrieving resolution list
[DEBUG:2025-07-28 16:16:34,213:xrandr]: Retrieving 59 video modes from XrandR

Output from flatpak run net.lutris.Lutris -d:

flatpak run net.lutris.Lutris -d
Gtk-Message: 16:15:42.487: Failed to load module “xapp-gtk3-module”
INFO 2025-07-28 16:15:42,928 [application.do_command_line:478]:Starting Lutris 0.5.19
INFO 2025-07-28 16:15:42,951 [startup.run_all_checks:120]:“card1” is Intel Iris Xe Graphics (8086:46a6 1043:277d i915) Driver 25.0.7
INFO 2025-07-28 16:15:43,085 [startup.run_all_checks:120]:“card2” is NVIDIA GeForce RTX 4060 Laptop GPU (10de:28e0 1043:277d nvidia) Driver 550.163.01
DEBUG 2025-07-28 16:15:43,170 [xrandr.get_resolutions:91]:Retrieving resolution list
DEBUG 2025-07-28 16:15:43,205 [xrandr._get_vidmodes:18]:Retrieving 59 video modes from XrandR
DEBUG 2025-07-28 16:15:43,242 [path_cache._update_missing_games:114]:Checking for missing games
DEBUG 2025-07-28 16:15:43,266 [api.check_stale_runtime_versions:52]:Modified at Po 28. júl 2025, 16:06:41, will update after Po 28. júl 2025, 22:06:41
DEBUG 2025-07-28 16:15:43,267 [lutriswindow.create_runtime_updater_cb:1384]:Runtime up to date
DEBUG 2025-07-28 16:15:44,245 [http._request:88]:POST https://lutris.net/api/users/library?since=1753711602
DEBUG 2025-07-28 16:16:32,507 [xrandr.get_outputs:26]:Retrieving display outputs
DEBUG 2025-07-28 16:16:34,081 [xrandr._get_vidmodes:18]:Retrieving 59 video modes from XrandR
DEBUG 2025-07-28 16:16:34,083 [xrandr.get_outputs:26]:Retrieving display outputs
DEBUG 2025-07-28 16:16:34,112 [xrandr._get_vidmodes:18]:Retrieving 59 video modes from XrandR
DEBUG 2025-07-28 16:16:34,114 [xrandr.get_resolutions:91]:Retrieving resolution list
DEBUG 2025-07-28 16:16:34,146 [xrandr._get_vidmodes:18]:Retrieving 59 video modes from XrandR
DEBUG 2025-07-28 16:16:34,151 [xrandr.get_resolutions:91]:Retrieving resolution list
DEBUG 2025-07-28 16:16:34,179 [xrandr._get_vidmodes:18]:Retrieving 59 video modes from XrandR
DEBUG 2025-07-28 16:16:34,182 [xrandr.get_resolutions:91]:Retrieving resolution list
DEBUG 2025-07-28 16:16:34,213 [xrandr._get_vidmodes:18]:Retrieving 59 video modes from XrandR

System info:

Vulkan support: YES
Esync support: YES
Fsync support: YES
Wine installed: YES
Gamescope: NO
Mangohud: NO
Gamemode: YES
Steam: YES
In Flatpak: YES
[System]
OS: GNOME 46 Flatpak runtime
Arch: x86_64
Kernel: 6.8.0-64-generic
Lutris Version: 0.5.19
Desktop: X-Cinnamon
Display Server: x11
[CPU]
Vendor: GenuineIntel
Model: 12th Gen Intel(R) Core™ i7-12700H
Physical cores: 14
Logical cores: 20
[Memory]
RAM: 15.2 GB
Swap: 26.1 GB
[Graphics]
Vendor: Intel
OpenGL Renderer: Mesa Intel(R) Iris(R) Xe Graphics (ADL GT2)
OpenGL Version: 4.6 (Compatibility Profile) Mesa 25.0.7 (git-742a20f48c)
OpenGL Core: 4.6 (Core Profile) Mesa 25.0.7 (git-742a20f48c)
OpenGL ES: OpenGL ES 3.2 Mesa 25.0.7 (git-742a20f48c)
Vulkan Version: 1.3.261
Vulkan Drivers: Intel(R) Iris(R) Xe Graphics (ADL GT2) (1.4.305), NVIDIA GeForce RTX 4060 Laptop GPU (1.3.277)

2

And this is the tutorial, I used at first:

Or should I rather use Lutris as system package instead of Flatpak or it doesn’t matter?

3

You seem to now understand that it’s your GTK+ styling. Lutris has always been “black” for me and I’ve always had it at “system default” for theme (moreover, I forgot that setting even existed in Preferences), because I use custom GTK styling with a lot of #000000 and #FFFFFF and some gradients for various GUI elements (scroll bars, buttons)

As far as I’m concerned, to beezleboob with that flatpak horseshit. It’s touted as a “good thing”, but it’s a kludge. One caveat to changing to the system package… while the package manager should pull in all the python dependencies and stuff, and Lutris should run, it could change the location of your configuration files.