diff --git a/settings/hyprland.nix b/settings/hyprland.nix
index c62934a..3f97f50 100644
--- a/settings/hyprland.nix
+++ b/settings/hyprland.nix
@@ -175,6 +175,10 @@ in
 
             render = {
               direct_scanout = false;
+              # Fullscreen video advertising HDR made Hyprland flip the monitor
+              # into HDR mode mid-playback (flicker + "wide color gamut ... not
+              # in 10-bit mode" toast, since DP-3 is 8-bit). Keep HDR off.
+              cm_auto_hdr = 0;
             };
 
             animations = {