Extract font configuration into a mixin

modules/mixins/fonts.nix

@@ -0,0 +1,31 @@
+{ pkgs, ... }:
+
+let
+  theme = import ../../lib/theme { inherit pkgs; };
+in
+{
+  fonts = {
+    fontconfig = {
+      enable = true;
+      defaultFonts = {
+        monospace = [ theme.fonts.monospace.name ];
+      };
+    };
+
+    packages =
+      with pkgs;
+      [
+        (nerdfonts.override {
+          fonts = [
+            "AnonymousPro"
+            "FiraCode"
+            "GeistMono"
+            "IntelOneMono"
+            "Iosevka"
+            "JetBrainsMono"
+          ];
+        })
+      ]
+      ++ [ theme.fonts.monospace.package ];
+  };
+}