diff --git a/darwin/profiles/core/nix/nix.nix b/darwin/profiles/core/nix/nix.nix
index 8d6881a..a200fe5 100755
--- a/darwin/profiles/core/nix/nix.nix
+++ b/darwin/profiles/core/nix/nix.nix
@@ -1,24 +1,23 @@
 {
   pkgs,
-  lib,
   config,
   ...
 }: {
   nix.settings = {
     trusted-users = ["@admin"];
     substituters =
-      lib.mkMerge
-      [
-        (lib.mkIf (config.time.timeZone == "Asia/Shanghai") [
+      {
+        "Asia/Shanghai" = [
           "https://mirrors.ustc.edu.cn/nix-channels/store" # USTC - 中国科学技术大学 Mirror
           "https://mirrors.tuna.tsinghua.edu.cn/nix-channels/store" # TUNA - 清华大学 Mirror
           "https://mirrors.bfsu.edu.cn/nix-channels/store" # BFSU - 北京外国语大学 Mirror
           "https://mirror.sjtu.edu.cn/nix-channels/store" # SJTU - 上海交通大学 Mirror
-        ])
-        [
-          "https://nix-community.cachix.org"
-          "https://cache.garnix.io"
-        ]
+        ];
+      }
+      .${config.time.timeZone}
+      ++ [
+        "https://nix-community.cachix.org"
+        "https://cache.garnix.io"
       ];
     trusted-public-keys = [
       "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
diff --git a/nixos/modules/networking/dns.nix b/nixos/modules/networking/dns.nix
index 466888d..bdcff6c 100644
--- a/nixos/modules/networking/dns.nix
+++ b/nixos/modules/networking/dns.nix
@@ -17,21 +17,23 @@ in {
   };
 
   config = {
-    networking.nameservers = lib.mkMerge [
-      (lib.mkIf (cfg.provider == "google") [
-        ### Google DNS
-        "8.8.8.8"
-        "8.8.4.4"
-        "2001:4860:4860::8888"
-        "2001:4860:4860::8844"
-      ])
-      (lib.mkIf (cfg.provider == "alidns") [
-        ### AliDNS
-        "223.5.5.5"
-        "223.6.6.6"
-        "2400:3200::1"
-        "2400:3200:baba::1"
-      ])
-    ];
+    networking.nameservers =
+      {
+        google = [
+          ### Google DNS
+          "8.8.8.8"
+          "8.8.4.4"
+          "2001:4860:4860::8888"
+          "2001:4860:4860::8844"
+        ];
+        alidns = [
+          ### AliDNS
+          "223.5.5.5"
+          "223.6.6.6"
+          "2400:3200::1"
+          "2400:3200:baba::1"
+        ];
+      }
+      .${cfg.provider};
   };
 }
diff --git a/nixos/profiles/core/nix/nix.nix b/nixos/profiles/core/nix/nix.nix
index 16bd75d..37eb401 100755
--- a/nixos/profiles/core/nix/nix.nix
+++ b/nixos/profiles/core/nix/nix.nix
@@ -1,23 +1,19 @@
-{
-  lib,
-  config,
-  ...
-}: {
+{config, ...}: {
   nix.settings = {
     trusted-users = ["@wheel"];
     substituters =
-      lib.mkMerge
-      [
-        (lib.mkIf (config.time.timeZone == "Asia/Shanghai") [
+      {
+        "Asia/Shanghai" = [
           "https://mirrors.ustc.edu.cn/nix-channels/store" # USTC - 中国科学技术大学 Mirror
           "https://mirrors.tuna.tsinghua.edu.cn/nix-channels/store" # TUNA - 清华大学 Mirror
           "https://mirrors.bfsu.edu.cn/nix-channels/store" # BFSU - 北京外国语大学 Mirror
           "https://mirror.sjtu.edu.cn/nix-channels/store" # SJTU - 上海交通大学 Mirror
-        ])
-        [
-          "https://nix-community.cachix.org"
-          "https://cache.garnix.io"
-        ]
+        ];
+      }
+      .${config.time.timeZone}
+      ++ [
+        "https://nix-community.cachix.org"
+        "https://cache.garnix.io"
       ];
     trusted-public-keys = [
       "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
@@ -33,13 +29,6 @@
   };
 
   system = {
-    # Copy the NixOS configuration file and link it from the resulting system
-    # (/run/current-system/configuration.nix). This is useful in case you
-    # accidentally delete configuration.nix.
-
-    # Does not work with flake based configurations
-    copySystemConfiguration = lib.mkDefault true;
-
     # This value determines the NixOS release from which the default
     # settings for stateful data, like file locations and database versions
     # on your system were taken. It's perfectly fine and recommended to leave
diff --git a/users/guanranwang/home-manager/applications/starship/default.nix b/users/guanranwang/home-manager/applications/starship/default.nix
index 8dd012c..75ac05d 100644
--- a/users/guanranwang/home-manager/applications/starship/default.nix
+++ b/users/guanranwang/home-manager/applications/starship/default.nix
@@ -1,11 +1,7 @@
-{
-  lib,
-  pkgs,
-  ...
-}: {
+{pkgs, ...}: {
   programs.starship = {
     enable = true;
-    settings = lib.mkMerge [
+    settings =
       {
         add_newline = false;
         line_break.disabled = true;
@@ -19,7 +15,6 @@
           vimcmd_visual_symbol = "[<](bold yellow)";
         };
       }
-      (builtins.fromTOML (builtins.readFile "${pkgs.starship}/share/starship/presets/nerd-font-symbols.toml"))
-    ];
+      // (builtins.fromTOML (builtins.readFile "${pkgs.starship}/share/starship/presets/nerd-font-symbols.toml"));
   };
 }