sway: remove gtk window decoration

user/sway.nix

@@ -188,7 +188,13 @@ in
             };
           floating = {
             modifier = "Mod4";
-            criteria = [{ class = "file_picker"; } { app_id = "file_picker"; }];
+            criteria = [
+              { class = "file_picker"; }
+              { app_id = "file_picker"; }
+              { app_id = "wdisplays"; }
+              { app_id = "pavucontrol"; }
+              { app_id = ".*[Hh]elvum.*"; }
+            ];
           };
           keybindings =
             let
@@ -471,6 +477,7 @@ in
       sway
       swaybg
       swaylock
+      wdisplays
 
       waybar
       dhist
@@ -509,5 +516,9 @@ in
       };
     };
     home.file = { ".local/share/backgrounds".source = ./backgrounds; };
+    home.sessionVariables = {
+      LD_PRELOAD = "${pkgs.gtk3-nocsd}/lib/libgtk3-nocsd.so.0";
+      GTK_CSD = "0";
+    };
   };
 }

user/theme.nix

@@ -24,7 +24,14 @@ in
       name = icon_theme;
       package = pkgs.papirus_red;
     };
-  };
+  } // (
+    let
+      shared.extraConfig = {
+        gtk-decoration-layout = "menu:";
+      };
+    in
+    { gtk4 = shared; gtk3 = shared; }
+  );
   # qt = {
   #   enable = true;
   #   platformTheme = "gtk";
@@ -39,6 +46,9 @@ in
       cursor-theme = cursor_theme;
       color-scheme = "prefer-${color.type}";
     };
+    "org/gnome/desktop/wm/preferences" = {
+      button-layout = "menu:";
+    };
   };
 
   # fonts.fontconfig.enable = true;