{ ... }:
{
  programs.niri.settings.window-rules = [
    {
      matches = [ { app-id = "^firefox$"; } ];
      default-column-width = {
        proportion = 0.66667;
      };
    }
    {
      matches = [ { title = "^Picture-in-Picture$"; } ];
      open-floating = true;
      default-floating-position = {
        x = 16;
        y = 16;
        relative-to = "bottom-right";
      };
    }
    {
      matches = [ { app-id = "^(pavucontrol|blueman-manager)$"; } ];
      open-floating = true;
    }
    {
      # Exemple : bordure/opacité par app
      matches = [ { app-id = "^kitty$"; } ];
      opacity = 0.95;
      geometry-corner-radius = {
        top-left = 8.0;
        top-right = 8.0;
        bottom-left = 8.0;
        bottom-right = 8.0;
      };
      clip-to-geometry = true;
    }
    {
      exclude-from-window-list = false;
      matches = [ { is-active = false; } ];
      opacity = 1.0;
    }
  ];
}