简化stable/unstable切换的方式；增加兼容性代码，根据版本引用

modules/nixos/fonts/default.nix

@@ -29,17 +29,19 @@
       source-han-serif # 思源宋体
 
       # wqy_zenhei # 文泉驿正黑
-
+    ] ++ (
       # nerdfonts
-      nerd-fonts.jetbrains-mono
-      # (nerdfonts.override {
-      #   fonts = [
-      #     # "FiraCode"
-      #     "JetBrainsMono"
-      #     # "Iosevka"
-      #   ];
-      # })
-
-    ];
+      if lib.versionAtLeast config.system.stateVersion "25.05" then
+        [ nerd-fonts.jetbrains-mono ]
+      else [
+        (nerdfonts.override {
+          fonts = [
+            # "FiraCode"
+            "JetBrainsMono"
+            # "Iosevka"
+          ];
+        })
+      ]
+    );
   };
 }