fix: try to make firefox the default browser

home/common/core.nix

@@ -1,8 +1,6 @@
-{config, pkgs, ...}: let
-  d = config.xdg.dataHome;
-  c = config.xdg.configHome;
-  cache = config.xdg.cacheHome;
-in rec {
+{config, pkgs, ...}: 
+
+{
   home.packages = with pkgs; [
     neofetch
     nnn          # terminal file manager
@@ -72,10 +70,6 @@ in rec {
     };
   };
 
-  services = {
-    # syncthing.enable = true;
-  };
-
   programs.bash = {
     enable = true;
     enableCompletion = true;
@@ -84,29 +78,6 @@ in rec {
     '';
   };
 
-  # add environment variables
-  systemd.user.sessionVariables = {
-    # clean up ~
-    LESSHISTFILE = cache + "/less/history";
-    LESSKEY = c + "/less/lesskey";
-    WINEPREFIX = d + "/wine";
-
-    # set this variable make i3 failed to start
-    # related issue:
-    #   https://github.com/sddm/sddm/issues/871
-    # XAUTHORITY = "$XDG_RUNTIME_DIR/Xauthority";
-
-    # set default applications
-    BROWSER = "firefox";
-    TERMINAL = "alacritty";
-
-    # enable scrolling in git diff
-    DELTA_PAGER = "less -R";
-
-    MANPAGER = "sh -c 'col -bx | bat -l man -p'";
-  };
-
-  home.sessionVariables = systemd.user.sessionVariables;
 
   home.shellAliases = {
     k = "kubectl";