A card game dims when menus change: check content adaptive brightness
If a laptop screen dims when a game switches from a bright menu to a dark card table, compare what happens to other visible parts of the screen. A change in the built-in display can affect more than the game’s own colors.
What to check
Some Windows 11 PCs change brightness and contrast based on displayed content. In System > Display > Brightness, look for the content setting and record its current state, including whether it applies only on battery. The separate ambient light option responds to room lighting.
Compare one example
Keep the room light steady. Open a bright and dark view in a second app and record whether the change also happens there. Compare plugged in and battery only if it is convenient. If dimming is isolated to the game and the desktop remains steady, capture the game screen and check its graphics settings separately.