Add Niri, a scrolling tiling window manager.

modules/home/wms/niri/theme/default.nix

@@ -0,0 +1,22 @@
+{ pkgs, config, ... }:
+{
+  config.home.niri.settings.theme = pkgs.writeText "theme" ''
+    prefer-no-csd
+    
+    layout {
+      gaps 7
+      center-focused-column "never"
+      default-column-width { proportion 0.5; }
+    
+      focus-ring {
+        off
+      }
+    
+      border {
+        width 3
+        active-color "#${config.look.colors.prime}"
+        inactive-color "#${config.look.colors.split}"
+      }
+    }
+  '';
+}