nix flake add systems input

flake.nix

@@ -1,14 +1,30 @@
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    flake-parts.url = "github:hercules-ci/flake-parts";
+    nixpkgs = {
+      url = "github:NixOS/nixpkgs/nixos-unstable";
+    };
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+      inputs.nixpkgs-lib.follows = "nixpkgs";
+    };
+    systems = {
+      url = "github:nix-systems/default";
+    };
   };
 
-  outputs = inputs@{ nixpkgs, flake-parts, ... }:
+  outputs = inputs @ {
+    nixpkgs,
+    flake-parts,
+    ...
+  }:
     flake-parts.lib.mkFlake {inherit inputs;} {
-      systems = [ "x86_64-linux" "aarch64-linux" ];
+      systems = import inputs.systems;
 
-      perSystem = { pkgs, system, ... }: {
+      perSystem = {
+        pkgs,
+        system,
+        ...
+      }: {
         devShells.default = pkgs.mkShell {packages = with pkgs; [pandoc];};
 
         packages.report = pkgs.stdenvNoCC.mkDerivation {
@@ -31,4 +47,3 @@
       };
     };
 }
-