refactor: flake.nix - adjust nixosConfigurations

flake.nix

@@ -108,7 +108,8 @@
 
     nixosSystem = import ./lib/nixosSystem.nix;
     macosSystem = import ./lib/macosSystem.nix;
-
+  in {
+    nixosConfigurations = let
       # 星野 アイ, Hoshino Ai
       idol_ai_modules_i3 = {
         nixos-modules = [
@@ -148,8 +149,7 @@
         ];
         home-module = import ./home/linux/server.nix;
       };
-  in {
-    nixosConfigurations = let
+
       system = x64_system;
       specialArgs =
         {
@@ -198,7 +198,7 @@
       );
 
     # macOS's configuration, for work.
-    darwinConfigurations."harmonica" = let
+    darwinConfigurations = let
       system = x64_darwin;
       specialArgs =
         {
@@ -211,13 +211,16 @@
           };
         }
         // inputs;
-    in
-      macosSystem {
+      base_args = {
         inherit nix-darwin home-manager system specialArgs;
+      };
+    in {
+      harmonica = macosSystem (base_args // {
         darwin-modules = [
           ./hosts/harmonica
         ];
         home-module = import ./home/darwin;
+      });
     };
 
     # format the nix code in this flake