They're two different files

home-manager/shared/shell/zellij.kdl

@@ -29,38 +29,3 @@ themes {
         white "#cad3f5"
     }
 }
-pane = {
-    default_tab_template {
-        children
-        pane size=1 borderless=true {
-            plugin location="file:${inputs.zjstatus.packages.${pkgs.system}.default}/bin/zjstatus.wasm" {
-                format_left   "{mode} #[fg=cyan,bold]{session}"
-                format_center "{tabs}"
-                format_right  "{command_git_branch} {datetime}"
-                format_space  ""
-
-                border_enabled  "false"
-                border_char     "─"
-                border_format   "#[fg=green]{char}"
-                border_position "top"
-
-                hide_frame_for_single_pane "true"
-
-                mode_normal  "#[bg=blue] "
-                mode_tmux    "#[bg=blue] "
-
-                tab_normal   "#[fg=green] {name} "
-                tab_active   "#[fg=red,bold,italic] {name} "
-
-                command_git_branch_command     "git rev-parse --abbrev-ref HEAD"
-                command_git_branch_format      "#[fg=blue] {stdout} "
-                command_git_branch_interval    "10"
-                command_git_branch_rendermode  "static"
-
-                datetime        "#[fg=#green,bold] {format} "
-                datetime_format "%A, %d %b %Y %H:%M"
-                datetime_timezone "Europe/Berlin"
-            }
-        }
-    }
-}

home-manager/shared/shell/zellij.nix

@@ -4,40 +4,9 @@
   inputs,
   ...
 }: let
-  config =
-    pkgs.writeText "config.kdl"
+  layout =
+    pkgs.writeText "default.kdl"
     ''
-      session_serialization true
-      theme "catppuccin-macchiato"
-
-      themes {
-          catppuccin-mocha {
-              bg "#585b70" // Surface2
-              fg "#cdd6f4"
-              red "#f38ba8"
-              green "#a6e3a1"
-              blue "#89b4fa"
-              yellow "#f9e2af"
-              magenta "#f5c2e7" // Pink
-              orange "#fab387" // Peach
-              cyan "#89dceb" // Sky
-              black "#181825" // Mantle
-              white "#cdd6f4"
-          }
-          catppuccin-macchiato {
-              bg "#5b6078" // Surface2
-              fg "#cad3f5"
-              red "#ed8796"
-              green "#a6da95"
-              blue "#8aadf4"
-              yellow "#eed49f"
-              magenta "#f5bde6" // Pink
-              orange "#f5a97f" // Peach
-              cyan "#91d7e3" // Sky
-              black "#1e2030" // Mantle
-              white "#cad3f5"
-          }
-      }
       layout {
           default_tab_template {
               children
@@ -83,8 +52,14 @@ in {
   };
 
   home.file = {
-    "zellij" = {
-      source = "${config}";
+    "layout" = {
+      source = "${layout}";
+      target = ".config/zellij/default.kdl";
+    };
+  };
+  home.file = {
+    "config" = {
+      source = ./zellij.kdl;
       target = ".config/zellij/config.kdl";
     };
   };