add alacritty custom config

configs/alacritty.nix

@@ -0,0 +1,48 @@
+{ pkgs, ... }:
+let
+  alacritty-cfg = theme:
+    (pkgs.formats.toml {}).generate "alacritty.toml" {
+      bell = {
+        animation = "EaseOut";
+        duration = 100;
+        color = "#ff00ff";
+      };
+      font = {
+        normal = {
+          family = "DejaVu Sans Mono";
+          style = "Regular";
+        };
+        bold = {
+          family = "DejaVu Sans Mono";
+          style = "Bold";
+        };
+        italic = {
+          family = "DejaVu Sans Mono";
+          style = "Italic";
+        };
+        bold_italic = {
+          family = "DejaVu Sans Mono";
+          style = "Bold Italic";
+        };
+        size = 7.2;
+      };
+    };
+in
+{
+  environment.variables.TERMINAL = "alacritty";
+
+  environment.etc."alacritty/default.toml".source = alacritty-cfg {
+  };
+
+  nixpkgs.overlays = [(self: super: {
+    alacritty-panda = pkgs.symlinkJoin {
+      name = "alacritty";
+      paths = [
+        (pkgs.writers.writeDashBin "alacritty" ''
+          exec ${pkgs.alacritty}/bin/alacritty --config-file /etc/alacritty/default.toml "$@"
+        '')
+        pkgs.alacritty
+      ];
+    };
+  })];
+} 

configuration.nix

@@ -8,6 +8,7 @@
   imports =
     [ # Include the results of the hardware scan.
       ./hardware-configuration.nix
+      ./configs/alacritty.nix
     ];
 
   # Bootloader.
@@ -98,6 +99,7 @@
     extraGroups = [ "networkmanager" "wheel" ];
     hashedPassword = "$y$j9T$jMcwkvhwodQHQRJ5c9Wg0/$YoLkfK3Frk9P5bXFneElJOTi2i8166RPzZEZ9hjamw8";
     packages = with pkgs; [
+      alacritty-panda # use alacritty wrapper defined in configs/alacritty.nix
       kdePackages.kate
       thunderbird
       cmatrix
@@ -140,7 +142,7 @@
     ];
 
     packages = [
-#      pkgs.alacritty-panda # use alacritty wrapper defined in configs/alacritty.nix
+      pkgs.alacritty-panda # use alacritty wrapper defined in configs/alacritty.nix
       pkgs.brave
       pkgs.firefox
       pkgs.firefox-devedition