Add package for kanagawa theme.

pkgs/kanagawa/default.nix

@@ -0,0 +1,29 @@
+{ lib, stdenv, fetchFromGitHub, gtk-engine-murrine }:
+
+stdenv.mkDerivation {
+  pname = "Kanagawa-GTK-Theme";
+  version = "1.0";
+
+  src = fetchFromGitHub {
+    owner = "Fausto-Korpsvart";
+    repo = "Kanagawa-GKT-Theme";
+    rev = "35936a1e3bbd329339991b29725fc1f67f192c1e";
+    sha256 = "sha256-BZRmjVas8q6zsYbXFk4bCk5Ec/3liy9PQ8fqFGHAXe0=";
+  };
+
+  propagatedUserEnvPkgs = [ gtk-engine-murrine ];
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out/share
+    cp -a themes $out/share/themes
+    runHook postInstall
+  '';
+
+  meta = with lib; {
+    description = "A GTK theme based on the colours of Rebelot's great theme: Kanagawa for Neovim, the VinceLiuice's awesome: Graphite GTK theme and the creativity of Gusbemacbe's: Suru Plus Icon Theme.";
+    homepage = "https://github.com/Fausto-Korpsvart/Kanagawa-GKT-Theme";
+    license = licenses.gpl3;
+    platforms = platforms.all;
+  };
+}

pkgs/nixpkgs.nix

@@ -19,6 +19,7 @@ in {
         theme_flat-remix = callPackage ./flat-remix {};
         theme_sddm_midnight = callPackage ./sddm_midnight {};
         xdiskusage = callPackage ./xdiskusage {};
+        kanagawa = callPackage ./kanagawa {};
       };
     };
     overlays = [