diff --git a/constants.nix b/constants.nix
new file mode 100644
index 00000000..b50514f5
--- /dev/null
+++ b/constants.nix
@@ -0,0 +1,15 @@
+rec {
+  # user information
+  username = "ryan";
+  userfullname = "Ryan Yin";
+  useremail = "xiaoyin_c@qq.com";
+
+  # linux systems
+  x64_system = "x86_64-linux";
+  riscv64_system = "riscv64-linux";
+  aarch64_system = "aarch64-linux";
+  # darwin systems
+  x64_darwin = "x86_64-darwin";
+  aarch64_darwin = "aarch64-darwin";
+  allSystems = [x64_system riscv64_system aarch64_system x64_darwin aarch64_darwin];
+}
diff --git a/flake.nix b/flake.nix
index 1c297434..c1f7eb8c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -16,284 +16,73 @@
   outputs = inputs @ {
     self,
     nixpkgs,
-    nixpkgs-unstable,
-    nixpkgs-darwin,
     pre-commit-hooks,
-    nix-darwin,
-    home-manager,
-    nixos-generators,
-    nixos-licheepi4a,
-    nixos-rk3588,
     ...
   }: let
-    username = "ryan";
-    userfullname = "Ryan Yin";
-    useremail = "xiaoyin_c@qq.com";
+    constants = import ./constants.nix;
 
-    x64_system = "x86_64-linux";
-    x64_darwin = "x86_64-darwin";
-    riscv64_system = "riscv64-linux";
-    aarch64_system = "aarch64-linux";
-    allSystems = [x64_system x64_darwin riscv64_system aarch64_system];
+    # FYI: `lib.genAttrs [ "foo" "bar" ] (name: "x_" + name)` => `{ foo = "x_foo"; bar = "x_bar"; }`
+    forEachSystem = func: (nixpkgs.lib.genAttrs constants.allSystems func);
 
-    nixosSystem = import ./lib/nixosSystem.nix;
-    macosSystem = import ./lib/macosSystem.nix;
-    colmenaSystem = import ./lib/colmenaSystem.nix;
-
-    # 星野 アイ, Hoshino Ai
-    idol_ai_modules_i3 = {
-      nixos-modules = [
-        ./hosts/idols/ai
-        ./modules/nixos/i3.nix
-      ];
-      home-module = import ./home/linux/desktop-i3.nix;
-    };
-    idol_ai_modules_hyprland = {
-      nixos-modules = [
-        ./hosts/idols/ai
-        ./modules/nixos/hyprland.nix
-      ];
-      home-module = import ./home/linux/desktop-hyprland.nix;
-    };
-
-    # 星野 愛久愛海, Hoshino Akuamarin
-    idol_aquamarine_modules = {
-      nixos-modules = [
-        ./hosts/idols/aquamarine
-      ];
-      home-module = import ./home/linux/server.nix;
-    };
-    idol_aquamarine_tags = ["dist-build" "aqua"];
-
-    # 星野 瑠美衣, Hoshino Rubii
-    idol_ruby_modules = {
-      nixos-modules = [
-        ./hosts/idols/ruby
-      ];
-      home-module = import ./home/linux/server.nix;
-    };
-    idol_ruby_tags = ["dist-build" "ruby"];
-
-    # 有馬 かな, Arima Kana
-    idol_kana_modules = {
-      nixos-modules = [
-        ./hosts/idols/kana
-      ];
-      home-module = import ./home/linux/server.nix;
-    };
-    idol_kana_tags = ["dist-build" "kana"];
-
-    # 森友 望未, Moritomo Nozomi
-    rolling_nozomi_modules = {
-      nixos-modules = [
-        ./hosts/rolling_girls/nozomi
-      ];
-      # home-module = import ./home/linux/server-riscv64.nix;
-    };
-    rolling_nozomi_tags = ["riscv" "nozomi"];
-
-    # 小坂 結季奈, Kosaka Yukina
-    rolling_yukina_modules = {
-      nixos-modules = [
-        ./hosts/rolling_girls/yukina
-      ];
-      # home-module = import ./home/linux/server-riscv64.nix;
-    };
-    rolling_yukina_tags = ["riscv" "yukina"];
-
-    # 大木 鈴, Ōki Suzu
-    _12kingdoms_suzu_modules = {
-      nixos-modules = [
-        ./hosts/12kingdoms/suzu
-      ];
-      # home-module = import ./home/linux/server.nix;
-    };
-    _12kingdoms_suzu_tags = ["aarch" "suzu"];
-
-    x64_specialArgs =
-      {
-        inherit username userfullname useremail;
-        # use unstable branch for some packages to get the latest updates
-        pkgs-unstable = import nixpkgs-unstable {
-          system = x64_system; # refer the `system` parameter form outer scope recursively
-          # To use chrome, we need to allow the installation of non-free software
-          config.allowUnfree = true;
-        };
-      }
-      // inputs;
-  in {
-    nixosConfigurations = let
-      base_args = {
-        inherit home-manager nixos-generators;
-        inherit nixpkgs; # or nixpkgs-unstable
-        system = x64_system;
-        specialArgs = x64_specialArgs;
-      };
-    in {
-      # ai with i3 window manager
-      ai_i3 = nixosSystem (idol_ai_modules_i3 // base_args);
-      # ai with hyprland compositor
-      ai_hyprland = nixosSystem (idol_ai_modules_hyprland // base_args);
-
-      # three virtual machines without desktop environment.
-      aquamarine = nixosSystem (idol_aquamarine_modules // base_args);
-      ruby = nixosSystem (idol_ruby_modules // base_args);
-      kana = nixosSystem (idol_kana_modules // base_args);
-    };
-
-    # colmena - remote deployment via SSH
-    colmena = let
-      # x86_64 related
-      x64_base_args = {
-        inherit home-manager;
-        inherit nixpkgs; # or nixpkgs-unstable
-        specialArgs = x64_specialArgs;
-      };
-
-      # riscv64 related
-      # using the same nixpkgs as nixos-licheepi4a to utilize the cross-compilation cache.
-      lpi4a_pkgs = import nixos-licheepi4a.inputs.nixpkgs {system = x64_system;};
-      lpi4a_specialArgs =
-        {
-          inherit username userfullname useremail;
-          pkgsKernel = nixos-licheepi4a.packages.${x64_system}.pkgsKernelCross;
-        }
-        // inputs;
-      lpi4a_base_args = {
-        inherit home-manager;
-        inherit (nixos-licheepi4a.inputs) nixpkgs; # or nixpkgs-unstable
-        specialArgs = lpi4a_specialArgs;
-        targetUser = "root";
-      };
-
-      # aarch64 related
-      # using the same nixpkgs as nixos-rk3588 to utilize the cross-compilation cache.
-      rk3588_pkgs = import nixos-rk3588.inputs.nixpkgs {system = x64_system;};
-      rk3588_specialArgs =
-        {
-          inherit username userfullname useremail;
-        }
-        // nixos-rk3588.inputs;
-      rk3588_base_args = {
-        inherit home-manager;
-        inherit (nixos-rk3588.inputs) nixpkgs; # or nixpkgs-unstable
-        specialArgs = rk3588_specialArgs;
-        targetUser = "root";
-      };
-    in {
-      meta = {
-        nixpkgs = import nixpkgs {system = x64_system;};
-        specialArgs = x64_specialArgs;
-
-        nodeSpecialArgs = {
-          # riscv64 SBCs
-          nozomi = lpi4a_specialArgs;
-          yukina = lpi4a_specialArgs;
-
-          # aarch64 SBCs
-          suzu = rk3588_specialArgs;
-        };
-        nodeNixpkgs = {
-          nozomi = lpi4a_pkgs;
-          yukina = lpi4a_pkgs;
-
-          # aarch64 SBCs
-          suzu = rk3588_pkgs;
-        };
-      };
-
-      # proxmox virtual machines(x86_64)
-      aquamarine = colmenaSystem (idol_aquamarine_modules // x64_base_args // {host_tags = idol_aquamarine_tags;});
-      ruby = colmenaSystem (idol_ruby_modules // x64_base_args // {host_tags = idol_ruby_tags;});
-      kana = colmenaSystem (idol_kana_modules // x64_base_args // {host_tags = idol_kana_tags;});
-
-      # riscv64 SBCs
-      nozomi = colmenaSystem (rolling_nozomi_modules // lpi4a_base_args // {host_tags = rolling_nozomi_tags;});
-      yukina = colmenaSystem (rolling_yukina_modules // lpi4a_base_args // {host_tags = rolling_yukina_tags;});
-
-      # aarch64 SBCs
-      suzu = colmenaSystem (_12kingdoms_suzu_modules // rk3588_base_args // {host_tags = _12kingdoms_suzu_tags;});
-    };
-
-    # take system images for idols
-    # https://github.com/nix-community/nixos-generators
-    packages."${x64_system}" =
-      # genAttrs returns an attribute set with the given keys and values(host => image).
-      nixpkgs.lib.genAttrs [
-        "ai_i3"
-        "ai_hyprland"
-      ]
-      (
-        # generate iso image for hosts with desktop environment
-        host:
-          self.nixosConfigurations.${host}.config.formats.iso
-      )
-      // nixpkgs.lib.genAttrs [
-        "aquamarine"
-        "ruby"
-        "kana"
-      ]
-      (
-        # generate proxmox image for virtual machines without desktop environment
-        host:
-          self.nixosConfigurations.${host}.config.formats.proxmox
+    allSystemConfigurations = import ./systems {inherit self inputs constants;};
+  in
+    allSystemConfigurations
+    // {
+      # format the nix code in this flake
+      # alejandra is a nix formatter with a beautiful output
+      formatter = forEachSystem (
+        system: nixpkgs.legacyPackages.${system}.alejandra
       );
 
-    # macOS's configuration, for work.
-    darwinConfigurations = let
-      system = x64_darwin;
-      specialArgs =
-        {
-          inherit username userfullname useremail;
-          # use unstable branch for some packages to get the latest updates
-          pkgs-unstable = import nixpkgs-unstable {
-            inherit system; # refer the `system` parameter form outer scope recursively
-            # To use chrome, we need to allow the installation of non-free software
-            config.allowUnfree = true;
+      # pre-commit hooks for nix code
+      checks = forEachSystem (
+        system: {
+          pre-commit-check = pre-commit-hooks.lib.${system}.run {
+            src = ./.;
+            hooks = {
+              alejandra.enable = true; # formatter
+              # deadnix.enable = true; # detect unused variable bindings in `*.nix`
+              statix.enable = true; # lints and suggestions for Nix code(auto suggestions)
+              prettier = {
+                enable = true;
+                excludes = [".js" ".md" ".ts"];
+              };
+            };
           };
         }
-        // inputs;
-      base_args = {
-        inherit nix-darwin home-manager system specialArgs;
-        nixpkgs = nixpkgs-darwin;
-      };
-    in {
-      harmonica = macosSystem (base_args
-        // {
-          darwin-modules = [
-            ./hosts/harmonica
-          ];
-          home-module = import ./home/darwin;
-        });
+      );
+      devShells = forEachSystem (
+        system: {
+          default = nixpkgs.legacyPackages.${system}.mkShell {
+            name = "dots";
+            shellHook = ''
+              ${self.checks.${system}.pre-commit-check.shellHook}
+            '';
+          };
+        }
+      );
     };
 
-    # format the nix code in this flake
-    # alejandra is a nix formatter with a beautiful output
-    formatter = nixpkgs.lib.genAttrs allSystems (
-      system:
-        nixpkgs.legacyPackages.${system}.alejandra
-    );
-
-    # pre-commit hooks for nix code
-    checks = nixpkgs.lib.genAttrs allSystems (
-      system: {
-        pre-commit-check = pre-commit-hooks.lib.${system}.run {
-          src = ./.;
-          hooks = {
-            alejandra.enable = true; # formatter
-            # deadnix.enable = true; # detect unused variable bindings in `*.nix`
-            statix.enable = true; # lints and suggestions for Nix code(auto suggestions)
-          };
-        };
-      }
-    );
-    devShells = nixpkgs.lib.genAttrs allSystems (
-      system: {
-        default = nixpkgs.legacyPackages.${system}.mkShell {
-          inherit (self.checks.${system}.pre-commit-check) shellHook;
-        };
-      }
-    );
+  # the nixConfig here only affects the flake itself, not the system configuration!
+  # for more information, see:
+  #     https://nixos-and-flakes.thiscute.world/nixos-with-flakes/add-custom-cache-servers
+  nixConfig = {
+    # substituers will be appended to the default substituters when fetching packages
+    extra-substituters = [
+      "https://nix-community.cachix.org"
+      # my own cache server
+      "https://ryan4yin.cachix.org"
+      "https://anyrun.cachix.org"
+      "https://hyprland.cachix.org"
+      # "https://nixpkgs-wayland.cachix.org"
+    ];
+    extra-trusted-public-keys = [
+      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+      "ryan4yin.cachix.org-1:Gbk27ZU5AYpGS9i3ssoLlwdvMIh0NxG0w8it/cv9kbU="
+      "anyrun.cachix.org-1:pqBobmOjI7nKlsUMV25u9QHa9btJK65/C8vnO3p346s="
+      "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
+      # "nixpkgs-wayland.cachix.org-1:3lwxaILxMRkVhehr5StQprHdEo4IrE8sRho9R9HOLYA="
+    ];
   };
 
   # This is the standard format for flake.nix. `inputs` are the dependencies of the flake,
@@ -444,26 +233,4 @@
       flake = false;
     };
   };
-
-  # the nixConfig here only affects the flake itself, not the system configuration!
-  # for more information, see:
-  #     https://nixos-and-flakes.thiscute.world/nixos-with-flakes/add-custom-cache-servers
-  nixConfig = {
-    # substituers will be appended to the default substituters when fetching packages
-    extra-substituters = [
-      "https://nix-community.cachix.org"
-      # my own cache server
-      "https://ryan4yin.cachix.org"
-      "https://anyrun.cachix.org"
-      "https://hyprland.cachix.org"
-      # "https://nixpkgs-wayland.cachix.org"
-    ];
-    extra-trusted-public-keys = [
-      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-      "ryan4yin.cachix.org-1:Gbk27ZU5AYpGS9i3ssoLlwdvMIh0NxG0w8it/cv9kbU="
-      "anyrun.cachix.org-1:pqBobmOjI7nKlsUMV25u9QHa9btJK65/C8vnO3p346s="
-      "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
-      # "nixpkgs-wayland.cachix.org-1:3lwxaILxMRkVhehr5StQprHdEo4IrE8sRho9R9HOLYA="
-    ];
-  };
 }
diff --git a/home/base/server/core.nix b/home/base/server/core.nix
index 4552d5ca..b8763d40 100644
--- a/home/base/server/core.nix
+++ b/home/base/server/core.nix
@@ -61,7 +61,7 @@
     # useful in bash/zsh prompt, not in nushell.
     eza = {
       enable = true;
-      enableAliases = false;  # do not enable aliases in nushell!
+      enableAliases = false; # do not enable aliases in nushell!
       git = true;
       icons = true;
     };
diff --git a/hosts/12kingdoms/suzu/default.nix b/hosts/12kingdoms/suzu/default.nix
index 01464f67..14e56db1 100644
--- a/hosts/12kingdoms/suzu/default.nix
+++ b/hosts/12kingdoms/suzu/default.nix
@@ -11,16 +11,9 @@
 #############################################################
 {
   imports = [
-    {
-      nixpkgs.crossSystem = {
-        config = "aarch64-unknown-linux-gnu";
-      };
-    }
 
     # import the rk3588 module, which contains the configuration for bootloader/kernel/firmware
     (nixos-rk3588 + "/modules/boards/orangepi5.nix")
-
-    ../../../modules/nixos/server-riscv64.nix
   ];
 
   users.users.root.openssh.authorizedKeys.keys = config.users.users."${username}".openssh.authorizedKeys.keys;
diff --git a/hosts/harmonica/default.nix b/hosts/harmonica/default.nix
index 16f47964..ebc2c901 100644
--- a/hosts/harmonica/default.nix
+++ b/hosts/harmonica/default.nix
@@ -7,14 +7,6 @@
 let
   hostname = "harmonica";
 in {
-  imports = [
-    ../../modules/darwin
-
-    ../../secrets/darwin.nix
-  ];
-
-  nixpkgs.overlays = import ../../overlays args;
-
   networking.hostName = hostname;
   networking.computerName = hostname;
   system.defaults.smb.NetBIOSName = hostname;
diff --git a/hosts/idols/ai/cifs-mount.nix b/hosts/idols/ai/cifs-mount.nix
index 645f67e8..ac344279 100644
--- a/hosts/idols/ai/cifs-mount.nix
+++ b/hosts/idols/ai/cifs-mount.nix
@@ -1,6 +1,5 @@
 {
   config,
-  pkgs,
   username,
   ...
 }: {
diff --git a/hosts/idols/ai/default.nix b/hosts/idols/ai/default.nix
index debafccd..dc87071a 100644
--- a/hosts/idols/ai/default.nix
+++ b/hosts/idols/ai/default.nix
@@ -1,4 +1,3 @@
-{lanzaboote, ...} @ args:
 #############################################################
 #
 #  Ai - my main computer, with NixOS + I5-13600KF + RTX 4090 GPU, for gaming & daily use.
@@ -12,12 +11,8 @@
 
     ./impermanence.nix
     ./secureboot.nix
-
-    ../../../secrets/nixos.nix
   ];
 
-  nixpkgs.overlays = import ../../../overlays args;
-
   networking = {
     hostName = "ai";
     wireless.enable = false; # Enables wireless support via wpa_supplicant.
diff --git a/hosts/idols/aquamarine/default.nix b/hosts/idols/aquamarine/default.nix
index 2927b529..4b0d00cd 100644
--- a/hosts/idols/aquamarine/default.nix
+++ b/hosts/idols/aquamarine/default.nix
@@ -1,18 +1,9 @@
-args:
 #############################################################
 #
 #  Aquamarine - A NixOS VM running on Proxmox
 #
 #############################################################
 {
-  imports = [
-    ../../../modules/nixos/proxmox-hardware-configuration.nix
-
-    ../../../modules/nixos/server.nix
-  ];
-
-  nixpkgs.overlays = import ../../../overlays args;
-
   # Enable binfmt emulation of aarch64-linux, this is required for cross compilation.
   boot.binfmt.emulatedSystems = ["aarch64-linux" "riscv64-linux"];
   # supported fil systems, so we can mount any removable disks with these filesystems
diff --git a/hosts/idols/kana/default.nix b/hosts/idols/kana/default.nix
index 772aec3a..22947f9d 100644
--- a/hosts/idols/kana/default.nix
+++ b/hosts/idols/kana/default.nix
@@ -1,18 +1,9 @@
-args:
 #############################################################
 #
 #  Kana - a NixOS VM running on Proxmox
 #
 #############################################################
 {
-  imports = [
-    ../../../modules/nixos/proxmox-hardware-configuration.nix
-
-    ../../../modules/nixos/server.nix
-  ];
-
-  nixpkgs.overlays = import ../../../overlays args;
-
   # Enable binfmt emulation of aarch64-linux, this is required for cross compilation.
   boot.binfmt.emulatedSystems = ["aarch64-linux" "riscv64-linux"];
   # supported fil systems, so we can mount any removable disks with these filesystems
diff --git a/hosts/idols/ruby/default.nix b/hosts/idols/ruby/default.nix
index 71091253..9e330b47 100644
--- a/hosts/idols/ruby/default.nix
+++ b/hosts/idols/ruby/default.nix
@@ -1,18 +1,9 @@
-args:
 #############################################################
 #
 #  Ruby - a NixOS VM running on Proxmox
 #
 #############################################################
 {
-  imports = [
-    ../../../modules/nixos/proxmox-hardware-configuration.nix
-
-    ../../../modules/nixos/server.nix
-  ];
-
-  nixpkgs.overlays = import ../../../overlays args;
-
   # Enable binfmt emulation of aarch64-linux, this is required for cross compilation.
   boot.binfmt.emulatedSystems = ["aarch64-linux" "riscv64-linux"];
   # supported fil systems, so we can mount any removable disks with these filesystems
diff --git a/hosts/rolling_girls/chiaya/default.nix b/hosts/rolling_girls/chiaya/default.nix
index 251ea633..ad35a160 100644
--- a/hosts/rolling_girls/chiaya/default.nix
+++ b/hosts/rolling_girls/chiaya/default.nix
@@ -1,9 +1,7 @@
 {
-  config,
-  username,
   # nixos-jh7110,
   ...
-} @ args:
+}:
 #############################################################
 #
 #  Chiaya - NixOS Configuration for Milk-V Mars
@@ -13,20 +11,8 @@
 #############################################################
 {
   imports = [
-    {
-      # cross-compilation this flake.
-      nixpkgs.crossSystem = {
-        system = "riscv64-linux";
-      };
-    }
-
-    # TODO
-
-    ../../../modules/nixos/server-riscv64.nix
   ];
 
-  users.users.root.openssh.authorizedKeys.keys = config.users.users."${username}".openssh.authorizedKeys.keys;
-
   # Set static IP address / gateway / DNS servers.
   networking = {
     hostName = "chiaya"; # Define your hostname.
@@ -64,5 +50,5 @@
   # this value at the release version of the first install of this system.
   # Before changing this value read the documentation for this option
   # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = "23.11"; # Did you read the comment?
+  system.stateVersion = "23.05"; # Did you read the comment?
 }
diff --git a/hosts/rolling_girls/nozomi/default.nix b/hosts/rolling_girls/nozomi/default.nix
index 62650cfb..8dce2913 100644
--- a/hosts/rolling_girls/nozomi/default.nix
+++ b/hosts/rolling_girls/nozomi/default.nix
@@ -1,9 +1,4 @@
-{
-  config,
-  username,
-  nixos-licheepi4a,
-  ...
-} @ args:
+{nixos-licheepi4a, ...}:
 #############################################################
 #
 #  Nozomi - NixOS configuration for Lichee Pi 4A
@@ -11,23 +6,12 @@
 #############################################################
 {
   imports = [
-    {
-      # cross-compilation this flake.
-      nixpkgs.crossSystem = {
-        system = "riscv64-linux";
-      };
-    }
-
     # import the licheepi4a module, which contains the configuration for bootloader/kernel/firmware
     (nixos-licheepi4a + "/modules/licheepi4a.nix")
     # import the sd-image module, which contains the fileSystems & kernel parameters for booting from sd card.
     (nixos-licheepi4a + "/modules/sd-image/sd-image-lp4a.nix")
-
-    ../../../modules/nixos/server-riscv64.nix
   ];
 
-  users.users.root.openssh.authorizedKeys.keys = config.users.users."${username}".openssh.authorizedKeys.keys;
-
   # Set static IP address / gateway / DNS servers.
   networking = {
     hostName = "nozomi"; # Define your hostname.
@@ -97,5 +81,5 @@
   # this value at the release version of the first install of this system.
   # Before changing this value read the documentation for this option
   # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = "23.11"; # Did you read the comment?
+  system.stateVersion = "23.05"; # Did you read the comment?
 }
diff --git a/hosts/rolling_girls/yukina/default.nix b/hosts/rolling_girls/yukina/default.nix
index 9249211b..0ff0098a 100644
--- a/hosts/rolling_girls/yukina/default.nix
+++ b/hosts/rolling_girls/yukina/default.nix
@@ -1,9 +1,4 @@
-{
-  config,
-  username,
-  nixos-licheepi4a,
-  ...
-} @ args:
+{nixos-licheepi4a, ...}:
 #############################################################
 #
 #  Yukina - NixOS configuration for Lichee Pi 4A
@@ -11,23 +6,12 @@
 #############################################################
 {
   imports = [
-    {
-      # cross-compilation this flake.
-      nixpkgs.crossSystem = {
-        system = "riscv64-linux";
-      };
-    }
-
     # import the licheepi4a module, which contains the configuration for bootloader/kernel/firmware
     (nixos-licheepi4a + "/modules/licheepi4a.nix")
     # import the sd-image module, which contains the fileSystems & kernel parameters for booting from sd card.
     (nixos-licheepi4a + "/modules/sd-image/sd-image-lp4a.nix")
-
-    ../../../modules/nixos/server-riscv64.nix
   ];
 
-  users.users.root.openssh.authorizedKeys.keys = config.users.users."${username}".openssh.authorizedKeys.keys;
-
   # Set static IP address / gateway / DNS servers.
   networking = {
     hostName = "yukina"; # Define your hostname.
@@ -97,5 +81,5 @@
   # this value at the release version of the first install of this system.
   # Before changing this value read the documentation for this option
   # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
-  system.stateVersion = "23.11"; # Did you read the comment?
+  system.stateVersion = "23.05"; # Did you read the comment?
 }
diff --git a/lib/colmenaSystem.nix b/lib/colmenaSystem.nix
index 3cf4b3b2..9da7b3be 100644
--- a/lib/colmenaSystem.nix
+++ b/lib/colmenaSystem.nix
@@ -10,10 +10,7 @@
 }: let
   inherit (specialArgs) username;
 in
-  {
-    name,
-    ...
-  }: {
+  {name, ...}: {
     deployment = {
       inherit targetUser;
       targetHost = name; # hostName or IP address
@@ -27,6 +24,8 @@ in
           # make `nix run nixpkgs#nixpkgs` use the same nixpkgs as the one used by this flake.
           nix.registry.nixpkgs.flake = nixpkgs;
           nix.channel.enable = false; # disable nix-channel, we use flakes instead.
+
+          nixpkgs.overlays = import ../overlays specialArgs;
         }
       ]
       ++ (
diff --git a/lib/macosSystem.nix b/lib/macosSystem.nix
index 44d581c4..966bd595 100644
--- a/lib/macosSystem.nix
+++ b/lib/macosSystem.nix
@@ -23,6 +23,8 @@ in
           # make `nix repl '<nixpkgs>'` use the same nixpkgs as the one used by this flake.
           # discard all the default paths, and only use the one from this flake.
           nix.nixPath = lib.mkForce ["/etc/nix/inputs"];
+
+          nixpkgs.overlays = import ../overlays specialArgs;
         })
 
         home-manager.darwinModules.home-manager
diff --git a/lib/nixosSystem.nix b/lib/nixosSystem.nix
index 101bd404..6ab11a0e 100644
--- a/lib/nixosSystem.nix
+++ b/lib/nixosSystem.nix
@@ -18,6 +18,8 @@ in
           # make `nix run nixpkgs#nixpkgs` use the same nixpkgs as the one used by this flake.
           nix.registry.nixpkgs.flake = nixpkgs;
           nix.channel.enable = false; # disable nix-channel, we use flakes instead.
+
+          nixpkgs.overlays = import ../overlays specialArgs;
         }
 
         nixos-generators.nixosModules.all-formats
diff --git a/modules/darwin/nix-core.nix b/modules/darwin/nix-core.nix
index 044af5a8..628c971a 100644
--- a/modules/darwin/nix-core.nix
+++ b/modules/darwin/nix-core.nix
@@ -1,7 +1,4 @@
-{
-  pkgs,
-  ...
-}: {
+{pkgs, ...}: {
   ###################################################################################
   #
   #  Core configuration for nix-darwin
diff --git a/modules/nixos/base/misc.nix b/modules/nixos/base/misc.nix
index cfba4d2f..d76bccbb 100644
--- a/modules/nixos/base/misc.nix
+++ b/modules/nixos/base/misc.nix
@@ -2,7 +2,8 @@
   lib,
   pkgs,
   ...
-}: {
+}:
+{
   ###################################################################################
   #
   #  NixOS's core configuration suitable for all my machines
diff --git a/modules/nixos/base/networking.nix b/modules/nixos/base/networking.nix
index 361e7348..0390a202 100644
--- a/modules/nixos/base/networking.nix
+++ b/modules/nixos/base/networking.nix
@@ -14,4 +14,6 @@
     };
     openFirewall = true;
   };
+
+
 }
diff --git a/modules/nixos/base/user-group.nix b/modules/nixos/base/user-group.nix
index 2bdce2be..e105c1f1 100644
--- a/modules/nixos/base/user-group.nix
+++ b/modules/nixos/base/user-group.nix
@@ -1,4 +1,4 @@
-{username, ...}: {
+{username, config, ...}: {
   # Don't allow mutation of users outside the config.
   users.mutableUsers = false;
 
@@ -37,10 +37,10 @@
       "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAII7PTkP3ixXTZlrJNSHnXgkmHNT+QslFi9wNYXOpVwGB ryan@harmonica"
     ];
   };
-  users.users.root.initialHashedPassword = "$7$CU..../....X6uvZYnFD.i1CqqFFNl4./$4vgqzIPyw5XBr0aCDFbY/UIRRJr7h5SMGoQ/ZvX3FP2";
-
-  # fix for `sudo xxx` in kitty/wezterm and other modern terminal emulators
-  security.sudo.keepTerminfo = true;
+  users.users.root = {
+    initialHashedPassword = "$7$CU..../....X6uvZYnFD.i1CqqFFNl4./$4vgqzIPyw5XBr0aCDFbY/UIRRJr7h5SMGoQ/ZvX3FP2";
+    openssh.authorizedKeys.keys = config.users.users."${username}".openssh.authorizedKeys.keys;
+  };
 
   # DO NOT promote the specified user to input password for `nix-store` and `nix-copy-closure`
   security.sudo.extraRules = [
diff --git a/modules/nixos/desktop/misc.nix b/modules/nixos/desktop/misc.nix
index 3f7acda3..0b07aff7 100644
--- a/modules/nixos/desktop/misc.nix
+++ b/modules/nixos/desktop/misc.nix
@@ -12,6 +12,9 @@
   # set user's default shell system-wide
   users.defaultUserShell = pkgs.nushell;
 
+  # fix for `sudo xxx` in kitty/wezterm and other modern terminal emulators
+  security.sudo.keepTerminfo = true;
+
   environment.variables = {
     # fix https://github.com/NixOS/nixpkgs/issues/238025
     TZ = "${config.time.timeZone}";
diff --git a/modules/nixos/server-riscv64.nix b/modules/nixos/server-riscv64.nix
index 7b74b6db..3a1538fc 100644
--- a/modules/nixos/server-riscv64.nix
+++ b/modules/nixos/server-riscv64.nix
@@ -3,20 +3,13 @@
   #      Base NixOS Configuration
   # =========================================================================
 
-  # Set your time zone.
-  time.timeZone = "Asia/Shanghai";
+  imports = [
+    ./base/i18n.nix
+    ./base/misc.nix
+    ./base/user-group.nix
 
-  # Select internationalisation properties.
-  i18n.defaultLocale = "en_US.UTF-8";
-
-  nix.settings = {
-    # Manual optimise storage: nix-store --optimise
-    # https://nixos.org/manual/nix/stable/command-ref/conf-file.html#conf-auto-optimise-store
-    auto-optimise-store = true;
-    builders-use-substitutes = true;
-    # enable flakes globally
-    experimental-features = ["nix-command" "flakes"];
-  };
+    ../base.nix
+  ];
 
   # List packages installed in system profile. To search, run:
   # $ nix search wget
@@ -51,9 +44,6 @@
     docker-compose
   ];
 
-  # replace default editor with neovim
-  environment.variables.EDITOR = "nvim";
-
   virtualisation.docker = {
     enable = true;
     # start dockerd on boot.
diff --git a/secrets/nixos.nix b/secrets/nixos.nix
index ec4f7be1..d586f23c 100644
--- a/secrets/nixos.nix
+++ b/secrets/nixos.nix
@@ -58,11 +58,11 @@
     # So we need to make then readable by the user
     "agenix/alias-for-work.nushell" = {
       source = config.age.secrets."alias-for-work.nushell".path;
-      mode = "0644";  # both the original file and the symlink should be readable and executable by the user
+      mode = "0644"; # both the original file and the symlink should be readable and executable by the user
     };
     "agenix/alias-for-work.bash" = {
       source = config.age.secrets."alias-for-work.bash".path;
-      mode = "0644";  # both the original file and the symlink should be readable and executable by the user
+      mode = "0644"; # both the original file and the symlink should be readable and executable by the user
     };
   };
 }
diff --git a/systems/colmena.nix b/systems/colmena.nix
new file mode 100644
index 00000000..fc91a4aa
--- /dev/null
+++ b/systems/colmena.nix
@@ -0,0 +1,102 @@
+args:
+with args; let
+  lib = nixpkgs.lib;
+  colmenaSystem = import ../lib/colmenaSystem.nix;
+  # x86_64 related
+  x64_base_args = {
+    inherit home-manager;
+    inherit nixpkgs; # or nixpkgs-unstable
+    specialArgs = x64_system_specialArgs;
+  };
+
+  # riscv64 related
+  # using the same nixpkgs as nixos-licheepi4a to utilize the cross-compilation cache.
+  lpi4a_pkgs = import nixos-licheepi4a.inputs.nixpkgs {system = x64_system;};
+  lpi4a_specialArgs =
+    {
+      inherit username userfullname useremail;
+      pkgsKernel = nixos-licheepi4a.packages.${x64_system}.pkgsKernelCross;
+    }
+    // args;
+  lpi4a_base_args = {
+    inherit home-manager;
+    inherit (nixos-licheepi4a.inputs) nixpkgs; # or nixpkgs-unstable
+    specialArgs = lpi4a_specialArgs;
+    targetUser = "root";
+  };
+
+  # aarch64 related
+  # using the same nixpkgs as nixos-rk3588 to utilize the cross-compilation cache.
+  rk3588_pkgs = import nixos-rk3588.inputs.nixpkgs {system = x64_system;};
+  rk3588_specialArgs =
+    {
+      inherit username userfullname useremail;
+    }
+    // nixos-rk3588.inputs;
+  rk3588_base_args = {
+    inherit home-manager;
+    inherit (nixos-rk3588.inputs) nixpkgs; # or nixpkgs-unstable
+    specialArgs = rk3588_specialArgs;
+    targetUser = "root";
+  };
+in {
+  # colmena - remote deployment via SSH
+  colmena = {
+    meta = {
+      nixpkgs = import nixpkgs {system = x64_system;};
+      specialArgs = x64_system_specialArgs;
+
+      nodeSpecialArgs = {
+        # riscv64 SBCs
+        nozomi = lpi4a_specialArgs;
+        yukina = lpi4a_specialArgs;
+
+        # aarch64 SBCs
+        suzu = rk3588_specialArgs;
+      };
+      nodeNixpkgs = {
+        nozomi = lpi4a_pkgs;
+        yukina = lpi4a_pkgs;
+
+        # aarch64 SBCs
+        suzu = rk3588_pkgs;
+      };
+    };
+
+    # proxmox virtual machines(x86_64)
+    aquamarine = colmenaSystem (lib.attrsets.mergeAttrsList [
+      x64_base_args
+      idol_aquamarine_modules
+      {host_tags = idol_aquamarine_tags;}
+    ]);
+    ruby = colmenaSystem (lib.attrsets.mergeAttrsList [
+      x64_base_args
+      idol_ruby_modules
+      {host_tags = idol_ruby_tags;}
+    ]);
+    kana = colmenaSystem (lib.attrsets.mergeAttrsList [
+      x64_base_args
+      idol_kana_modules
+      {host_tags = idol_kana_tags;}
+    ]);
+
+    # riscv64 SBCs
+    nozomi = colmenaSystem (lib.attrsets.mergeAttrsList [
+      lpi4a_base_args
+      rolling_nozomi_modules
+      {host_tags = rolling_nozomi_tags;}
+    ]);
+    yukina = colmenaSystem (lib.attrsets.mergeAttrsList [
+      lpi4a_base_args
+      rolling_yukina_modules
+      {host_tags = rolling_yukina_tags;}
+    ]);
+
+    # aarch64 SBCs
+    suzu = colmenaSystem (lib.attrsets.mergeAttrsList [
+      rk3588_base_args
+      _12kingdoms_suzu_modules
+      {host_tags = _12kingdoms_suzu_tags;}
+    ]);
+  };
+}
diff --git a/systems/darwin.nix b/systems/darwin.nix
new file mode 100644
index 00000000..b1d33a94
--- /dev/null
+++ b/systems/darwin.nix
@@ -0,0 +1,17 @@
+args:
+with args; let
+  macosSystem = import ../lib/macosSystem.nix;
+  system = x64_darwin;
+  base_args = {
+    inherit nix-darwin home-manager system;
+    specialArgs = x64_darwin_specialArgs;
+    nixpkgs = nixpkgs-darwin;
+  };
+in {
+  # macOS's configuration, for work.
+  darwinConfigurations = {
+    harmonica =
+      macosSystem (base_args
+        // darwin_harmonica_modules);
+  };
+}
diff --git a/systems/default.nix b/systems/default.nix
new file mode 100644
index 00000000..8f1dc31b
--- /dev/null
+++ b/systems/default.nix
@@ -0,0 +1,42 @@
+{
+  self,
+  inputs,
+  constants,
+}: let
+  lib = inputs.nixpkgs.lib;
+  vars = import ./vars.nix;
+
+  specialArgsForSystem = system:
+    {
+      inherit (constants) username userfullname useremail;
+      # use unstable branch for some packages to get the latest updates
+      pkgs-unstable = import inputs.nixpkgs-unstable {
+        inherit system; # refer the `system` parameter form outer scope recursively
+        # To use chrome, we need to allow the installation of non-free software
+        config.allowUnfree = true;
+      };
+    }
+    // inputs;
+
+  allSystemSpecialArgs = with constants; {
+    x64_system_specialArgs = specialArgsForSystem x64_system;
+    aarch64_system_specialArgs = specialArgsForSystem aarch64_system;
+    riscv64_system_specialArgs = specialArgsForSystem riscv64_system;
+
+    x64_darwin_specialArgs = specialArgsForSystem x64_darwin;
+    aarch64_darwin_specialArgs = specialArgsForSystem aarch64_darwin;
+  };
+
+  args = lib.attrsets.mergeAttrsList [
+    inputs
+    constants
+    vars
+    allSystemSpecialArgs
+    {inherit self;}
+  ];
+in
+  lib.attrsets.mergeAttrsList [
+    (import ./nixos.nix args)
+    (import ./darwin.nix args)
+    (import ./colmena.nix args)
+  ]
diff --git a/systems/nixos.nix b/systems/nixos.nix
new file mode 100644
index 00000000..fb0b75ab
--- /dev/null
+++ b/systems/nixos.nix
@@ -0,0 +1,47 @@
+args:
+with args; let
+  nixosSystem = import ../lib/nixosSystem.nix;
+
+  base_args = {
+    inherit home-manager nixos-generators;
+    inherit nixpkgs; # or nixpkgs-unstable
+    system = x64_system;
+    specialArgs = x64_system_specialArgs;
+  };
+in {
+  nixosConfigurations = {
+    # ai with i3 window manager
+    ai_i3 = nixosSystem (idol_ai_modules_i3 // base_args);
+    # ai with hyprland compositor
+    ai_hyprland = nixosSystem (idol_ai_modules_hyprland // base_args);
+
+    # three virtual machines without desktop environment.
+    aquamarine = nixosSystem (idol_aquamarine_modules // base_args);
+    ruby = nixosSystem (idol_ruby_modules // base_args);
+    kana = nixosSystem (idol_kana_modules // base_args);
+  };
+
+  # take system images for idols
+  # https://github.com/nix-community/nixos-generators
+  packages."${x64_system}" =
+    # genAttrs returns an attribute set with the given keys and values(host => image).
+    nixpkgs.lib.genAttrs [
+      "ai_i3"
+      "ai_hyprland"
+    ]
+    (
+      # generate iso image for hosts with desktop environment
+      host:
+        self.nixosConfigurations.${host}.config.formats.iso
+    )
+    // nixpkgs.lib.genAttrs [
+      "aquamarine"
+      "ruby"
+      "kana"
+    ]
+    (
+      # generate proxmox image for virtual machines without desktop environment
+      host:
+        self.nixosConfigurations.${host}.config.formats.proxmox
+    );
+}
diff --git a/systems/vars.nix b/systems/vars.nix
new file mode 100644
index 00000000..61fb1c6b
--- /dev/null
+++ b/systems/vars.nix
@@ -0,0 +1,102 @@
+{
+  # 星野 アイ, Hoshino Ai
+  idol_ai_modules_i3 = {
+    nixos-modules = [
+      ../hosts/idols/ai
+      ../secrets/nixos.nix
+      ../modules/nixos/i3.nix
+    ];
+    home-module = import ../home/linux/desktop-i3.nix;
+  };
+  idol_ai_modules_hyprland = {
+    nixos-modules = [
+      ../hosts/idols/ai
+      ../secrets/nixos.nix
+      ../modules/nixos/hyprland.nix
+    ];
+    home-module = import ../home/linux/desktop-hyprland.nix;
+  };
+
+  # 星野 愛久愛海, Hoshino Akuamarin
+  idol_aquamarine_modules = {
+    nixos-modules = [
+      ../hosts/idols/aquamarine
+      ../modules/nixos/server.nix
+      ../modules/nixos/proxmox-hardware-configuration.nix
+    ];
+    home-module = import ../home/linux/server.nix;
+  };
+  idol_aquamarine_tags = ["dist-build" "aqua"];
+
+  # 星野 瑠美衣, Hoshino Rubii
+  idol_ruby_modules = {
+    nixos-modules = [
+      ../hosts/idols/ruby
+      ../modules/nixos/server.nix
+      ../modules/nixos/proxmox-hardware-configuration.nix
+    ];
+    home-module = import ../home/linux/server.nix;
+  };
+  idol_ruby_tags = ["dist-build" "ruby"];
+
+  # 有馬 かな, Arima Kana
+  idol_kana_modules = {
+    nixos-modules = [
+      ../hosts/idols/kana
+      ../modules/nixos/server.nix
+      ../modules/nixos/proxmox-hardware-configuration.nix
+    ];
+    home-module = import ../home/linux/server.nix;
+  };
+  idol_kana_tags = ["dist-build" "kana"];
+
+  # 森友 望未, Moritomo Nozomi
+  rolling_nozomi_modules = {
+    nixos-modules = [
+      ../hosts/rolling_girls/nozomi
+      ../modules/nixos/server-riscv64.nix
+
+      # cross-compilation this flake.
+      {nixpkgs.crossSystem.system = "riscv64-linux";}
+    ];
+    # home-module = import ../home/linux/server-riscv64.nix;
+  };
+  rolling_nozomi_tags = ["riscv" "nozomi"];
+
+  # 小坂 結季奈, Kosaka Yukina
+  rolling_yukina_modules = {
+    nixos-modules = [
+      ../hosts/rolling_girls/yukina
+      ../modules/nixos/server-riscv64.nix
+
+      # cross-compilation this flake.
+      {nixpkgs.crossSystem.system = "riscv64-linux";}
+    ];
+    # home-module = import ../home/linux/server-riscv64.nix;
+  };
+  rolling_yukina_tags = ["riscv" "yukina"];
+
+  # 大木 鈴, Ōki Suzu
+  _12kingdoms_suzu_modules = {
+    nixos-modules = [
+      ../hosts/12kingdoms/suzu
+      ../modules/nixos/server-riscv64.nix
+
+      # cross-compilation this flake.
+      {nixpkgs.crossSystem.config = "aarch64-unknown-linux-gnu";}
+    ];
+    # home-module = import ../home/linux/server.nix;
+  };
+  _12kingdoms_suzu_tags = ["aarch" "suzu"];
+
+  # darwin systems
+  darwin_harmonica_modules = {
+    darwin-modules = [
+      ../hosts/harmonica
+
+      ../modules/darwin
+      ../secrets/darwin.nix
+    ];
+    home-module = import ../home/darwin;
+  };
+}