3 files changed, 75 insertions, 1 deletions
diff --git a/modules/desktop/niri/default.nix b/modules/desktop/niri/default.nix
index f1e0fa7..7fbb5fb 100644
--- a/modules/desktop/niri/default.nix
+++ b/modules/desktop/niri/default.nix
@@ -21,7 +21,6 @@
         CLUTTER_BACKEND = "wayland";
         GDK_SCALE = "1";
         QT_SCALE_FACTOR = "1";
-        GTK_THEME = "Adwaita:dark";
       }
 
       (lib.mkIf config.desktop.hardware.gpu.nvidia.enable {
@@ -41,6 +40,8 @@
     wayland.windowManager.niri = {
       enable = true;
       systemd.enable = true;
+      # Portals are declared centrally in ../xdg.
+      portalPackage = null;
     };
 
     # Niri does not paint wallpapers itself, so start swaybg with the existing wallpaper.
diff --git a/modules/desktop/xdg/default.nix b/modules/desktop/xdg/default.nix
index 852b36c..3803502 100644
--- a/modules/desktop/xdg/default.nix
+++ b/modules/desktop/xdg/default.nix
@@ -5,13 +5,25 @@
   pkgs,
   ...
 }:
+let
+  gtkCss = builtins.readFile (
+    config.scheme {
+      template = builtins.readFile ./style.mustache.css;
+      extension = ".css";
+    }
+  );
+in
 {
   config = lib.mkIf config.desktop.enable {
+    dconf.enable = true;
+
     xdg.portal = {
       enable = true;
       extraPortals = with pkgs; [
         xdg-desktop-portal-termfilechooser
+        xdg-desktop-portal-gnome
       ];
+      configPackages = [ pkgs.niri ];
       config.common = {
         "org.freedesktop.impl.portal.FileChooser" = [ "termfilechooser" ];
         default = [
@@ -21,5 +33,34 @@
       };
       xdgOpenUsePortal = true;
     };
+
+    gtk = {
+      enable = true;
+      font = {
+        name = config.fonts.normal;
+        size = config.fonts.size;
+      };
+      theme = {
+        name = "Adwaita-dark";
+        package = pkgs.gnome-themes-extra;
+      };
+      iconTheme = {
+        name = "Adwaita";
+        package = pkgs.adwaita-icon-theme;
+      };
+      cursorTheme = {
+        name = "Adwaita";
+        package = pkgs.adwaita-icon-theme;
+        size = 20;
+      };
+      colorScheme = "dark";
+      gtk3.extraCss = gtkCss;
+      gtk4 = {
+        # GTK 4/libadwaita does not support loading GTK 3 themes; use the
+        # Base16 CSS above without Home Manager's compatibility workaround.
+        theme = null;
+        extraCss = gtkCss;
+      };
+    };
   };
 }
diff --git a/modules/desktop/xdg/style.mustache.css b/modules/desktop/xdg/style.mustache.css
new file mode 100644
index 0000000..d7a5420
--- /dev/null
+++ b/modules/desktop/xdg/style.mustache.css
@@ -0,0 +1,32 @@
+@define-color theme_bg_color #{{base00}};
+@define-color theme_fg_color #{{base05}};
+@define-color theme_base_color #{{base00}};
+@define-color theme_text_color #{{base05}};
+@define-color theme_selected_bg_color #{{base0D}};
+@define-color theme_selected_fg_color #{{base00}};
+@define-color borders #{{base03}};
+@define-color accent_color #{{base0D}};
+@define-color warning_color #{{base0A}};
+@define-color error_color #{{base08}};
+
+window, dialog, .background {
+  background-color: @theme_bg_color;
+  color: @theme_fg_color;
+}
+
+button, entry, textview, .view, list, row {
+  background-color: @theme_base_color;
+  color: @theme_text_color;
+  border-color: @borders;
+  border-radius: 0;
+  box-shadow: none;
+}
+
+button:hover, entry:focus {
+  border-color: @accent_color;
+}
+
+selection, row:selected, flowboxchild:selected {
+  background-color: @theme_selected_bg_color;
+  color: @theme_selected_fg_color;
+}