nix-configs/modules/desktop-environment/home/compositing.nix

{...}: {
  services.picom = {
    enable = true;
    backend = "glx";

    shadow = true;
    shadowOffsets = [(-40) (-30)];
    shadowOpacity = 0.2;
    shadowExclude = [
      "class_g ?= 'Notify-osd'"
      "_GTK_FRAME_EXTENTS@:c"
      "!(class_g = 'Rofi' || class_g = 'Dunst')"
    ];

    vSync = true;
    settings = {
      "shadow-radius" = 40;
      # fading rofi
      "fading" = true;
      "fade-in-step" = 0.25;
      "fade-out-step" = 0.2;
      "fade-delta" = 20;
      "fade-exclude" = ["class_g != 'Rofi'"];
      # use damage information
      "use-damage" = true;
    };
  };
}