diff --git a/.gitignore b/.gitignore
index d91a8fe..e381515 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,11 +14,12 @@ common/cinnamon/cinnamon-dark.css
 common/cinnamon/cinnamon.css
 common/gnome-shell/**/gnome-shell-dark.css
 common/gnome-shell/**/gnome-shell.css
-common/gtk-3.0/**/gtk-dark.css
-common/gtk-3.0/**/gtk-darker.css
-common/gtk-3.0/**/gtk.css
+common/gtk-3.0/**/*.css
+common/gtk-3.0/**/light/
+common/gtk-3.0/**/darker/
+common/gtk-3.0/**/dark/
 common/gtk-3.0/**/assets/*.png
-common/gtk-2.0/assets*/*.png
+common/gtk-2.0/*/assets/*.png
 common/gtk-2.0/menubar-toolbar/*.png
-common/xfwm4/assets*/*.png
+common/xfwm4/*/assets/*.png
 common/compile-gresources.sh
diff --git a/Makefile.am b/Makefile.am
index 3ac2276..d8e16eb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -4,7 +4,6 @@ EXTRA_DIST = \
 	README.md \
 	HACKING.md \
 	autogen.sh \
-	gulpfile.js \
 	package.json \
 	.nvmrc
 
diff --git a/README.md b/README.md
index 5b11152..6ee16a3 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,6 @@ To build the theme the following packages are required
 * `inkscape`
 
 The following packages are optionally required
-* `parallel` for speeding up build by rendering assets in parallel
 * `gnome-shell`for auto-detecting the GNOME Shell version
 * `libgtk-3-dev` for Debian based distros or `gtk3-devel` for RPM based distros, for auto-detecting the GTK3 version
 
diff --git a/common/Makefile.am b/common/Makefile.am
index 02a7e6e..50aebf1 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -1,11 +1,27 @@
-if !ENABLE_TRANSPARENCY
-themedir        = $(datadir)/themes/Arc-solid
-themedarkerdir  = $(datadir)/themes/Arc-Darker-solid
-themedarkdir    = $(datadir)/themes/Arc-Dark-solid
-else
-themedir        = $(datadir)/themes/Arc
-themedarkerdir  = $(datadir)/themes/Arc-Darker
-themedarkdir    = $(datadir)/themes/Arc-Dark
+if ENABLE_GTK2
+GTK2_SUBDIR = gtk-2.0
+endif
+
+if ENABLE_GTK3
+GTK3_SUBDIR = gtk-3.0
+endif
+
+if ENABLE_XFWM
+XFWM_SUBDIR = xfwm4
+endif
+
+SUBDIRS = $(GTK2_SUBDIR) $(GTK3_SUBDIR) $(XFWM_SUBDIR)
+
+if ENABLE_LIGHT
+theme_DATA = $(srcdir)/index/light/index.theme
+endif
+
+if ENABLE_DARKER
+themedarker_DATA = $(srcdir)/index/darker/index.theme
+endif
+
+if ENABLE_DARK
+themedark_DATA = $(srcdir)/index/dark/index.theme
 endif
 
 ithemedir       = $(DESTDIR)$(themedir)
@@ -16,28 +32,12 @@ install-exec-hook:
 
 install-data-local:
 
-if ENABLE_LIGHT
-	$(MKDIR_P) $(ithemedir)
-	cp $(srcdir)/index.theme $(ithemedir)
-endif # ENABLE_LIGHT
-
-if ENABLE_DARKER
-	$(MKDIR_P) $(ithemedarkerdir)
-	cp $(srcdir)/index.theme-darker $(ithemedarkerdir)/index.theme
-endif # ENABLE_LIGHT
-
-if ENABLE_DARK
-	$(MKDIR_P) $(ithemedarkdir)
-	cp $(srcdir)/index.theme-dark $(ithemedarkdir)/index.theme
-endif # ENABLE_DARK
-
-
 if ENABLE_CINNAMON
 	$(MKDIR_P) $(ithemedir)/cinnamon
 
 	cd $(srcdir)/cinnamon && cp thumbnail.png $(ithemedir)/cinnamon
 
-	sassc $(srcdir)/cinnamon/sass/cinnamon.scss $(srcdir)/cinnamon/cinnamon.css;
+	$(SASSC) $(srcdir)/cinnamon/sass/cinnamon.scss $(srcdir)/cinnamon/cinnamon.css;
 
 	cd $(srcdir)/cinnamon && cp -R \
 		common-assets \
@@ -50,7 +50,7 @@ if ENABLE_DARK
 
 	cd $(srcdir)/cinnamon && cp thumbnail-dark.png $(ithemedarkdir)/cinnamon/thumbnail.png
 
-	sassc $(srcdir)/cinnamon/sass/cinnamon-dark.scss $(srcdir)/cinnamon/cinnamon-dark.css;
+	$(SASSC) $(srcdir)/cinnamon/sass/cinnamon-dark.scss $(srcdir)/cinnamon/cinnamon-dark.css;
 
 	cd $(srcdir)/cinnamon && cp -R \
 		common-assets \
@@ -68,7 +68,7 @@ endif # ENABLE_GNOME_SHELL
 if ENABLE_GNOME_SHELL
 	$(MKDIR_P) $(ithemedir)/gnome-shell
 
-	sassc $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/sass/gnome-shell.scss $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/gnome-shell.css;
+	$(SASSC) $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/sass/gnome-shell.scss $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/gnome-shell.css;
 
 	cd $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION) && cp -RL \
 		common-assets \
@@ -79,7 +79,7 @@ if ENABLE_GNOME_SHELL
 if ENABLE_DARK
 	$(MKDIR_P) $(ithemedarkdir)/gnome-shell
 
-	sassc $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/sass/gnome-shell-dark.scss $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/gnome-shell-dark.css;
+	$(SASSC) $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/sass/gnome-shell-dark.scss $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION)/gnome-shell-dark.css;
 
 	cd $(srcdir)/gnome-shell/$(GNOME_SHELL_VERSION) && cp -RL \
 		common-assets \
@@ -94,166 +94,6 @@ endif # ENABLE_DARK
 endif # ENABLE_GNOME_SHELL
 
 
-if ENABLE_GTK2
-	cd $(srcdir)/gtk-2.0 && $(MKDIR_P) assets assets-dark && ./render-assets.sh
-
-if ENABLE_LIGHT
-	$(MKDIR_P) $(ithemedir)/gtk-2.0
-
-	cd $(srcdir)/gtk-2.0 && cp -R \
-		assets \
-		menubar-toolbar \
-		*.rc \
-		gtkrc \
-		$(ithemedir)/gtk-2.0
-endif # ENABLE_LIGHT
-
-if ENABLE_DARKER
-	$(MKDIR_P) $(ithemedarkerdir)/gtk-2.0
-
-	cd $(srcdir)/gtk-2.0 && cp -R \
-		assets \
-		menubar-toolbar \
-		*.rc \
-		$(ithemedarkerdir)/gtk-2.0
-
-	cd $(srcdir)/gtk-2.0 && cp -R \
-		gtkrc-darker \
-		$(ithemedarkerdir)/gtk-2.0/gtkrc
-endif # ENABLE_DARKER
-
-if ENABLE_DARK
-	$(MKDIR_P) $(ithemedarkdir)/gtk-2.0
-
-	cd $(srcdir)/gtk-2.0 && cp -R \
-		menubar-toolbar \
-		*.rc \
-		$(ithemedarkdir)/gtk-2.0
-
-	cd $(srcdir)/gtk-2.0 && cp -R \
-		assets-dark \
-		$(ithemedarkdir)/gtk-2.0/assets
-
-	cd $(srcdir)/gtk-2.0 && cp -R \
-		gtkrc-dark \
-		$(ithemedarkdir)/gtk-2.0/gtkrc
-endif # ENABLE_DARK
-
-endif # ENABLE_GTK2
-
-
-if ENABLE_GTK3
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && $(MKDIR_P) assets && ./render-assets.sh
-
-if ENABLE_LIGHT
-	$(MKDIR_P) $(ithemedir)/gtk-3.0
-
-	cd $(srcdir)/gtk-3.0 && cp thumbnail.png $(ithemedir)/gtk-3.0
-
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-dark.css;
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		assets \
-		gtk.css \
-		gtk-dark.css \
-		$(ithemedir)/gtk-3.0
-endif # ENABLE_LIGHT
-
-if ENABLE_DARKER
-	$(MKDIR_P) $(ithemedarkerdir)/gtk-3.0
-
-	cd $(srcdir)/gtk-3.0 && cp thumbnail.png $(ithemedarkerdir)/gtk-3.0
-
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-dark.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-darker.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-darker.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk.css;
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		assets \
-		gtk-dark.css \
-		$(ithemedarkerdir)/gtk-3.0
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-darker.css \
-		$(ithemedarkerdir)/gtk-3.0/gtk.css
-endif # ENABLE_DARKER
-
-if ENABLE_DARK
-	$(MKDIR_P) $(ithemedarkdir)/gtk-3.0
-
-	cd $(srcdir)/gtk-3.0 && cp thumbnail-dark.png $(ithemedarkdir)/gtk-3.0/thumbnail.png
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		assets \
-		$(ithemedarkdir)/gtk-3.0
-
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-dark.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk.css;
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-dark.css \
-		$(ithemedarkdir)/gtk-3.0/gtk.css
-endif # ENABLE_DARK
-
-if !ENABLE_TRANSPARENCY
-
-if ENABLE_LIGHT
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-solid.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-solid.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-solid-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-solid-dark.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-dark.css;
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-solid.css \
-		$(ithemedir)/gtk-3.0/gtk.css
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-solid-dark.css \
-		$(ithemedir)/gtk-3.0/gtk-dark.css
-endif # ENABLE_LIGHT
-
-if ENABLE_DARKER
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-solid-darker.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-solid-darker.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-solid-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-solid-dark.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-dark.css;
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-solid-darker.css \
-		$(ithemedarkerdir)/gtk-3.0/gtk.css
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-solid-dark.css \
-		$(ithemedarkerdir)/gtk-3.0/gtk-dark.css
-endif # ENABLE_DARKER
-
-if ENABLE_DARK
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk-solid-dark.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk-solid-dark.css;
-	sassc $(srcdir)/gtk-3.0/$(GTK3_VERSION)/sass/gtk.scss $(srcdir)/gtk-3.0/$(GTK3_VERSION)/gtk.css;
-
-	cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -R \
-		gtk-solid-dark.css \
-		$(ithemedarkdir)/gtk-3.0/gtk.css
-endif # ENABLE_DARK
-
-endif #!ENABLE_TRANSPARENCY
-
-	@if [ "$(GTK_VERSION)" != "3.18" ]; then \
-		cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -RL compile-gresources.sh $(ithemedir)/gtk-3.0/compile-gresources.sh;\
-		cd ../..;\
-		cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -RL compile-gresources.sh $(ithemedarkdir)/gtk-3.0/compile-gresources.sh;\
-		cd ../..;\
-		cd $(srcdir)/gtk-3.0/$(GTK3_VERSION) && cp -RL compile-gresources.sh $(ithemedarkerdir)/gtk-3.0/compile-gresources.sh;\
-		cd ../..;\
-		cd $(ithemedir)/gtk-3.0/ && ./compile-gresources.sh LIGHT;\
-		cd $(ithemedarkdir)/gtk-3.0/ && ./compile-gresources.sh DARK;\
-		cd $(ithemedarkerdir)/gtk-3.0/ && ./compile-gresources.sh DARKER;\
-	fi
-
-endif # ENABLE_GTK3
-
-
 if ENABLE_METACITY
 
 if ENABLE_LIGHT
@@ -326,36 +166,6 @@ endif # ENABLE_DARK
 endif # ENABLE_UNITY
 
 
-if ENABLE_XFWM
-	cd $(srcdir)/xfwm4 && $(MKDIR_P) assets assets-dark && ./render-assets.sh
-
-if ENABLE_LIGHT
-	$(MKDIR_P) $(ithemedir)/xfwm4
-
-	cd $(srcdir)/xfwm4 && \
-		cp -R assets/*.png $(ithemedir)/xfwm4 && \
-		cp themerc $(ithemedir)/xfwm4/themerc
-endif # ENABLE_LIGHT
-
-if ENABLE_DARKER
-	$(MKDIR_P) $(ithemedarkerdir)/xfwm4
-
-	cd $(srcdir)/xfwm4 && \
-		cp -R assets-dark/*.png $(ithemedarkerdir)/xfwm4 && \
-		cp themerc-dark $(ithemedarkerdir)/xfwm4/themerc
-endif # ENABLE_DARKER
-
-if ENABLE_DARK
-	$(MKDIR_P) $(ithemedarkdir)/xfwm4
-
-	cd $(srcdir)/xfwm4 && \
-		cp -R assets-dark/*.png $(ithemedarkdir)/xfwm4 && \
-		cp themerc-dark $(ithemedarkdir)/xfwm4/themerc
-endif # ENABLE_DARK
-
-endif # ENABLE_XFWM
-
-
 uninstall-local:
 	rm -rf $(ithemedir)
 
@@ -368,13 +178,9 @@ if ENABLE_DARK
 endif # ENABLE_DARK
 
 
-EXTRA_DIST = $(srcdir)/cinnamon \
-	     $(srcdir)/gnome-shell \
-	     $(srcdir)/gtk-2.0 \
-	     $(srcdir)/gtk-3.0 \
-	     $(srcdir)/metacity-1 \
-	     $(srcdir)/unity \
-	     $(srcdir)/xfwm4 \
-	     $(srcdir)/index.theme \
-	     $(srcdir)/index.theme-darker \
-	     $(srcdir)/index.theme-dark
+EXTRA_DIST = \
+	cinnamon \
+	gnome-shell \
+	index \
+	metacity-1 \
+	unity
diff --git a/common/gtk-2.0/Makefile.am b/common/gtk-2.0/Makefile.am
new file mode 100644
index 0000000..069bc1d
--- /dev/null
+++ b/common/gtk-2.0/Makefile.am
@@ -0,0 +1,78 @@
+VPATH =
+
+targets := $(shell cat $(srcdir)/assets.txt)
+light := $(patsubst %,light/assets/%.png,$(targets))
+dark := $(patsubst %,dark/assets/%.png,$(targets))
+
+mbt_entry := $(filter entry-%toolbar,$(targets))
+mbt_menubar := $(filter menubar%,$(targets))
+mbt_button := $(filter button%,$(targets))
+
+mbt_light := \
+	$(srcdir)/menubar-toolbar/menubar-toolbar.rc \
+	$(patsubst %,menubar-toolbar/%.png,$(mbt_entry) $(mbt_menubar))
+
+mbt_dark := \
+	$(srcdir)/menubar-toolbar/menubar-toolbar-dark.rc \
+	$(patsubst %,menubar-toolbar/%-dark.png,$(mbt_entry) $(mbt_menubar)) \
+	$(patsubst %,menubar-toolbar/%.png,$(mbt_button))
+
+rc := apps main panel xfce-notify
+srcrc := $(patsubst %,$(srcdir)/%.rc,$(rc))
+
+light: $(light)
+dark: $(dark)
+mbt_light: $(mbt_light)
+mbt_dark: $(mbt_dark)
+
+light/assets dark/assets menubar-toolbar:
+	$(MKDIR_P) "$@"/
+
+clean:
+	rm -rf light/assets/ dark/assets/ menubar-toolbar/*.png
+
+$(light): $(srcdir)/light/assets.svg | light/assets
+$(dark): $(srcdir)/dark/assets.svg | dark/assets
+
+$(light) $(dark):
+	$(INKSCAPE) --export-id-only --export-png="$@" --export-id="$(basename $(notdir $@))" --export-dpi=$(if $(filter $(OPTION_GTK2_HIDPI),true),192,96) "$<" >/dev/null
+	$(OPTIPNG) -o7 --quiet "$@"
+
+menubar-toolbar/%-dark.png: dark/assets/%.png | menubar-toolbar
+	cp "$<" "$@"
+
+menubar-toolbar/%.png: light/assets/%.png | menubar-toolbar
+	cp "$<" "$@"
+
+.PHONY: light dark mbt_light mbt_dark clean
+
+if ENABLE_LIGHT
+gtk2themedir = $(themedir)/gtk-2.0
+gtk2themeassetsdir = $(gtk2themedir)/assets
+gtk2theme_DATA = $(srcrc) $(srcdir)/light/gtkrc
+gtk2themeassets_DATA = $(light)
+nobase_gtk2theme_DATA = $(mbt_light)
+endif
+
+if ENABLE_DARKER
+gtk2themedarkerdir = $(themedarkerdir)/gtk-2.0
+gtk2themedarkerassetsdir = $(gtk2themedarkerdir)/assets
+gtk2themedarker_DATA = $(srcrc) $(srcdir)/darker/gtkrc
+gtk2themedarkerassets_DATA = $(light)
+nobase_gtk2themedarker_DATA = $(mbt_dark)
+endif
+
+if ENABLE_DARK
+gtk2themedarkdir = $(themedarkdir)/gtk-2.0
+gtk2themedarkassetsdir = $(gtk2themedarkdir)/assets
+gtk2themedark_DATA = $(srcrc) $(srcdir)/dark/gtkrc
+gtk2themedarkassets_DATA = $(dark)
+nobase_gtk2themedark_DATA = $(mbt_dark)
+endif
+
+EXTRA_DIST = \
+	assets.txt \
+	$(srcrc) \
+	$(patsubst %,%/assets.svg,light dark) \
+	$(patsubst %,%/gtkrc,light darker dark) \
+	$(patsubst %,menubar-toolbar/menubar-toolbar%,.rc -dark.rc)
diff --git a/common/gtk-2.0/assets-dark.svg b/common/gtk-2.0/dark/assets.svg
similarity index 100%
rename from common/gtk-2.0/assets-dark.svg
rename to common/gtk-2.0/dark/assets.svg
diff --git a/common/gtk-2.0/gtkrc-dark b/common/gtk-2.0/dark/gtkrc
similarity index 100%
rename from common/gtk-2.0/gtkrc-dark
rename to common/gtk-2.0/dark/gtkrc
diff --git a/common/gtk-2.0/gtkrc-darker b/common/gtk-2.0/darker/gtkrc
similarity index 100%
rename from common/gtk-2.0/gtkrc-darker
rename to common/gtk-2.0/darker/gtkrc
diff --git a/common/gtk-2.0/assets.svg b/common/gtk-2.0/light/assets.svg
similarity index 100%
rename from common/gtk-2.0/assets.svg
rename to common/gtk-2.0/light/assets.svg
diff --git a/common/gtk-2.0/gtkrc b/common/gtk-2.0/light/gtkrc
similarity index 100%
rename from common/gtk-2.0/gtkrc
rename to common/gtk-2.0/light/gtkrc
diff --git a/common/gtk-2.0/render-asset.sh b/common/gtk-2.0/render-asset.sh
deleted file mode 100755
index 590d3d1..0000000
--- a/common/gtk-2.0/render-asset.sh
+++ /dev/null
@@ -1,29 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-INKSCAPE="$(which inkscape)"
-OPTIPNG="$(which optipng)"
-
-ASSETS_DIR="$1"
-SRC_FILE="${ASSETS_DIR}".svg
-
-i="$2"
-
-
-result_file="$ASSETS_DIR/$i.png"
-if [[ -f "${result_file}" ]] ; then
-	echo "${result_file} already exists."
-else
-	echo "Rendering '${result_file}'"
-	if [[ "${OPTION_GTK2_HIDPI:-false}" != "true" ]]; then
-		"$INKSCAPE" --export-id="$i" \
-					--export-id-only \
-					--export-png="${result_file}" "$SRC_FILE" >/dev/null
-	else
-		"$INKSCAPE" --export-id="$i" \
-					--export-id-only \
-					--export-dpi=192 \
-					--export-png="${result_file}" "$SRC_FILE" >/dev/null
-	fi
-	"$OPTIPNG" -o7 --quiet "${result_file}"
-fi
diff --git a/common/gtk-2.0/render-assets.sh b/common/gtk-2.0/render-assets.sh
deleted file mode 100755
index 5cf4be7..0000000
--- a/common/gtk-2.0/render-assets.sh
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-# Make sure that parallel is GNU parallel and not moreutils.
-# Otherwise, it fails silently. There's no smooth way to detect this.
-if [[ "$(which parallel 2> /dev/null)" ]]; then
-  cmd=(parallel)
-else
-  cmd=(xargs -n1)
-fi
-
-
-ASSETS_DIR="assets"
-DARK_ASSETS_DIR="assets-dark"
-
-
-"${cmd[@]}" ./render-asset.sh ${ASSETS_DIR} < assets.txt
-"${cmd[@]}" ./render-asset.sh ${DARK_ASSETS_DIR} < assets.txt
-
-
-cp $ASSETS_DIR/entry-toolbar.png menubar-toolbar/entry-toolbar.png
-cp $ASSETS_DIR/entry-active-toolbar.png menubar-toolbar/entry-active-toolbar.png
-cp $ASSETS_DIR/entry-disabled-toolbar.png menubar-toolbar/entry-disabled-toolbar.png
-
-cp $ASSETS_DIR/menubar.png menubar-toolbar/menubar.png
-cp $ASSETS_DIR/menubar_button.png menubar-toolbar/menubar_button.png
-
-
-cp $DARK_ASSETS_DIR/button.png menubar-toolbar/button.png
-cp $DARK_ASSETS_DIR/button-hover.png menubar-toolbar/button-hover.png
-cp $DARK_ASSETS_DIR/button-active.png menubar-toolbar/button-active.png
-cp $DARK_ASSETS_DIR/button-insensitive.png menubar-toolbar/button-insensitive.png
-
-cp $DARK_ASSETS_DIR/entry-toolbar.png menubar-toolbar/entry-toolbar-dark.png
-cp $DARK_ASSETS_DIR/entry-active-toolbar.png menubar-toolbar/entry-active-toolbar-dark.png
-cp $DARK_ASSETS_DIR/entry-disabled-toolbar.png menubar-toolbar/entry-disabled-toolbar-dark.png
-
-cp $DARK_ASSETS_DIR/menubar.png menubar-toolbar/menubar-dark.png
-cp $DARK_ASSETS_DIR/menubar_button.png menubar-toolbar/menubar_button-dark.png
-
-exit 0
diff --git a/common/gtk-3.0/3.18/Makefile.am b/common/gtk-3.0/3.18/Makefile.am
new file mode 100644
index 0000000..6c3c7e0
--- /dev/null
+++ b/common/gtk-3.0/3.18/Makefile.am
@@ -0,0 +1,31 @@
+include ../common.am
+
+light/gtk.css: gtk.css | light
+	cp "$<" "$@"
+light/gtk-dark.css: gtk-dark.css | light
+	cp "$<" "$@"
+darker/gtk.css: gtk-darker.css | darker
+	cp "$<" "$@"
+darker/gtk-dark.css: gtk-dark.css | darker
+	cp "$<" "$@"
+dark/gtk.css: gtk-dark.css | dark
+	cp "$<" "$@"
+
+gtk3themeassetsdir = $(gtk3themedir)/assets
+gtk3themedarkerassetsdir = $(gtk3themedarkerdir)/assets
+gtk3themedarkassetsdir = $(gtk3themedarkdir)/assets
+
+if ENABLE_LIGHT
+gtk3theme_DATA = light/gtk.css light/gtk-dark.css
+gtk3themeassets_DATA = $(normal) $(hidpi)
+endif
+
+if ENABLE_DARKER
+gtk3themedarker_DATA = darker/gtk.css darker/gtk-dark.css
+gtk3themedarkerassets_DATA = $(normal) $(hidpi)
+endif
+
+if ENABLE_DARK
+gtk3themedark_DATA = dark/gtk.css
+gtk3themedarkassets_DATA = $(normal) $(hidpi)
+endif
diff --git a/common/gtk-3.0/3.18/render-asset.sh b/common/gtk-3.0/3.18/render-asset.sh
deleted file mode 100755
index 7d460a7..0000000
--- a/common/gtk-3.0/3.18/render-asset.sh
+++ /dev/null
@@ -1,23 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-INKSCAPE="$(which inkscape)"
-OPTIPNG="$(which optipng)"
-
-SRC_FILE="assets.svg"
-ASSETS_DIR="assets"
-
-i="$1"
-
-echo "Rendering '$ASSETS_DIR/$i.png'"
-"$INKSCAPE" --export-id="$i" \
-            --export-id-only \
-            --export-png="$ASSETS_DIR/$i.png" "$SRC_FILE" >/dev/null \
-&& "$OPTIPNG" -o7 --quiet "$ASSETS_DIR/$i.png"
-
-echo "Rendering '$ASSETS_DIR/$i@2.png'"
-"$INKSCAPE" --export-id="$i" \
-            --export-id-only \
-            --export-dpi=192 \
-            --export-png="$ASSETS_DIR/$i@2.png" "$SRC_FILE" >/dev/null \
-&& "$OPTIPNG" -o7 --quiet "$ASSETS_DIR/$i@2.png"
diff --git a/common/gtk-3.0/3.18/render-assets.sh b/common/gtk-3.0/3.18/render-assets.sh
deleted file mode 100755
index 6634c78..0000000
--- a/common/gtk-3.0/3.18/render-assets.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-# Make sure that parallel is GNU parallel and not moreutils.
-# Otherwise, it fails silently. There's no smooth way to detect this.
-if [[ "$(which parallel 2> /dev/null)" ]]; then
-  cmd=(parallel)
-else
-  cmd=(xargs -n1)
-fi
-
-"${cmd[@]}" ./render-asset.sh < assets.txt
diff --git a/common/gtk-3.0/3.20/Makefile.am b/common/gtk-3.0/3.20/Makefile.am
new file mode 100644
index 0000000..6a04a37
--- /dev/null
+++ b/common/gtk-3.0/3.20/Makefile.am
@@ -0,0 +1,35 @@
+include ../common.am
+
+light/gtk-main.css: gtk.css | light
+	cp "$<" "$@"
+light/gtk-main-dark.css: gtk-dark.css | light
+	cp "$<" "$@"
+darker/gtk-main.css: gtk-darker.css | darker
+	cp "$<" "$@"
+darker/gtk-main-dark.css: gtk-dark.css | darker
+	cp "$<" "$@"
+dark/gtk-main.css: gtk-dark.css | dark
+	cp "$<" "$@"
+dark/gtk-main-dark.css: | dark
+	touch "$@"
+
+%/gtk.css %/gtk-dark.css: | %
+	echo '@import url("resource:///org/gnome/arc-theme/$(subst gtk,gtk-main,$(notdir $@))");' > "$@"
+
+%/gtk.gresource.xml: | %
+	echo "<?xml version='1.0' encoding='UTF-8'?><gresources><gresource prefix='/org/gnome/arc-theme'>$(patsubst %,<file preprocess='to-pixdata'>../%</file>,$(normal) $(hidpi))<file>gtk-main.css</file>$(if $(filter $(dir $@),dark/),,<file>gtk-main-dark.css</file>)</gresource></gresources>" > "$@"
+
+%/gtk.gresource: %/gtk.gresource.xml %/gtk-main.css %/gtk-main-dark.css $(normal) $(hidpi)
+	glib-compile-resources --sourcedir="$(dir $<)" --target="$@" "$<"
+
+if ENABLE_LIGHT
+gtk3theme_DATA = light/gtk.css light/gtk-dark.css light/gtk.gresource
+endif
+
+if ENABLE_DARKER
+gtk3themedarker_DATA = darker/gtk.css darker/gtk-dark.css darker/gtk.gresource
+endif
+
+if ENABLE_DARK
+gtk3themedark_DATA = dark/gtk.css dark/gtk.gresource
+endif
diff --git a/common/gtk-3.0/3.20/compile-gresources.sh b/common/gtk-3.0/3.20/compile-gresources.sh
deleted file mode 100755
index 1e92df5..0000000
--- a/common/gtk-3.0/3.20/compile-gresources.sh
+++ /dev/null
@@ -1,56 +0,0 @@
-#!/bin/bash
-
-# Setup
-mv gtk.css gtk-main.css
-if [ "$1" != "DARK" ]; then
-    mv gtk-dark.css gtk-main-dark.css
-fi
-
-# Get processed assets lists
-ls ./assets | sort > temp_asset_list.txt
-
-
-# Build dynamic gresouce xml spec from css and assets
-read -d '' RES_PART1 <<"EOF"
-<?xml version="1.0" encoding="UTF-8"?>
-<gresources>
-<gresource prefix="/org/gnome/arc-theme">
-EOF
-echo $RES_PART1 > gtk.gresource.xml
-
-
-# Import as nodes the file assets
-xargs -i echo '<file preprocess="to-pixdata">assets/{}</file>' >> gtk.gresource.xml < temp_asset_list.txt
-rm -f temp_asset_list.txt
-
-
-# Write the css file information to the template
-if [ "$1" != "DARK" ]; then
-    read -d '' RES_PART2 <<"EOF"
-<file>gtk-main.css</file>
-<file>gtk-main-dark.css</file>
-</gresource>
-</gresources>
-EOF
-else
-    read -d '' RES_PART2 <<"EOFDARK"
-<file>gtk-main.css</file>
-</gresource>
-</gresources>
-EOFDARK
-fi
-echo $RES_PART2 >> gtk.gresource.xml
-
-# Compile the gresource file
-glib-compile-resources gtk.gresource.xml
-echo '@import url("resource:///org/gnome/arc-theme/gtk-main.css");' > gtk.css
-if [ "$1" != "DARK" ]; then
-    echo '@import url("resource:///org/gnome/arc-theme/gtk-main-dark.css");' > gtk-dark.css
-fi
-
-# Cleanup
-rm -rf assets
-rm -f gtk.gresource.xml
-rm -f gtk-main.css
-rm -f gtk-main-dark.css
-rm -f compile-gresources.sh
diff --git a/common/gtk-3.0/3.20/render-asset.sh b/common/gtk-3.0/3.20/render-asset.sh
deleted file mode 100755
index 3d84f2d..0000000
--- a/common/gtk-3.0/3.20/render-asset.sh
+++ /dev/null
@@ -1,28 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-INKSCAPE="$(which inkscape)"
-OPTIPNG="$(which optipng)"
-
-SRC_FILE="assets.svg"
-ASSETS_DIR="assets"
-
-i="$1"
-
-result_file="$ASSETS_DIR/$i.png"
-if [[ -f "${result_file}" ]] ; then
-	echo "${result_file} already exists."
-else
-	echo "Rendering '$ASSETS_DIR/$i.png'"
-	"$INKSCAPE" --export-id="$i" \
-	            --export-id-only \
-	            --export-png="$ASSETS_DIR/$i.png" "$SRC_FILE" >/dev/null \
-	&& "$OPTIPNG" -o7 --quiet "$ASSETS_DIR/$i.png"
-
-	echo "Rendering '$ASSETS_DIR/$i@2.png'"
-	"$INKSCAPE" --export-id="$i" \
-	            --export-id-only \
-	            --export-dpi=192 \
-	            --export-png="$ASSETS_DIR/$i@2.png" "$SRC_FILE" >/dev/null \
-	&& "$OPTIPNG" -o7 --quiet "$ASSETS_DIR/$i@2.png"
-fi
diff --git a/common/gtk-3.0/3.20/render-assets.sh b/common/gtk-3.0/3.20/render-assets.sh
deleted file mode 100755
index 6634c78..0000000
--- a/common/gtk-3.0/3.20/render-assets.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-# Make sure that parallel is GNU parallel and not moreutils.
-# Otherwise, it fails silently. There's no smooth way to detect this.
-if [[ "$(which parallel 2> /dev/null)" ]]; then
-  cmd=(parallel)
-else
-  cmd=(xargs -n1)
-fi
-
-"${cmd[@]}" ./render-asset.sh < assets.txt
diff --git a/common/gtk-3.0/3.22 b/common/gtk-3.0/3.22
deleted file mode 120000
index 8b6d177..0000000
--- a/common/gtk-3.0/3.22
+++ /dev/null
@@ -1 +0,0 @@
-3.20
\ No newline at end of file
diff --git a/common/gtk-3.0/3.24 b/common/gtk-3.0/3.24
deleted file mode 120000
index 8b6d177..0000000
--- a/common/gtk-3.0/3.24
+++ /dev/null
@@ -1 +0,0 @@
-3.20
\ No newline at end of file
diff --git a/common/gtk-3.0/Makefile.am b/common/gtk-3.0/Makefile.am
new file mode 100644
index 0000000..10a56e0
--- /dev/null
+++ b/common/gtk-3.0/Makefile.am
@@ -0,0 +1,19 @@
+if ENABLE_LIGHT
+gtk3theme_DATA = light/thumbnail.png
+endif
+
+if ENABLE_DARKER
+gtk3themedarker_DATA = light/thumbnail.png
+endif
+
+if ENABLE_DARK
+gtk3themedark_DATA = dark/thumbnail.png
+endif
+
+EXTRA_DIST = \
+	light \
+	dark \
+	_colors.scss.thpl
+
+SUBDIRS = $(GTK3_VERSION)
+DIST_SUBDIRS = 3.18 3.20
diff --git a/common/gtk-3.0/common.am b/common/gtk-3.0/common.am
new file mode 100644
index 0000000..9ecd171
--- /dev/null
+++ b/common/gtk-3.0/common.am
@@ -0,0 +1,39 @@
+VPATH =
+
+targets := $(shell cat $(srcdir)/assets.txt)
+normal := $(patsubst %,assets/%.png,$(targets))
+hidpi := $(patsubst %,assets/%@2.png,$(targets))
+
+normal: $(normal)
+hidpi: $(hidpi)
+
+assets light dark darker:
+	$(MKDIR_P) "$@"/
+
+clean:
+	rm -rf assets/ light/ dark/ darker/
+
+$(normal): $(srcdir)/assets.svg | assets
+	$(INKSCAPE) --export-id-only --export-png="$@" --export-id="$(basename $(notdir $@))" --export-dpi=96 "$<" >/dev/null
+	$(OPTIPNG) -o7 --quiet "$@"
+
+$(hidpi): $(srcdir)/assets.svg | assets
+	$(INKSCAPE) --export-id-only --export-png="$@" --export-id="$(patsubst %@2,%,$(basename $(notdir $@)))" --export-dpi=192 "$<" >/dev/null
+	$(OPTIPNG) -o7 --quiet "$@"
+
+.PHONY: normal hidpi clean
+
+if ENABLE_TRANSPARENCY
+%.css: $(srcdir)/sass/%.scss
+	$(SASSC) "$<" "$@"
+else
+gtk.css: $(srcdir)/sass/gtk-solid.scss
+	$(SASSC) "$<" "$@"
+gtk-%.css: $(srcdir)/sass/gtk-solid-%.scss
+	$(SASSC) "$<" "$@"
+endif
+
+EXTRA_DIST = \
+	assets.txt \
+	assets.svg \
+	sass
diff --git a/common/gtk-3.0/thumbnail-dark.png b/common/gtk-3.0/dark/thumbnail.png
similarity index 100%
rename from common/gtk-3.0/thumbnail-dark.png
rename to common/gtk-3.0/dark/thumbnail.png
diff --git a/common/gtk-3.0/thumbnail.png b/common/gtk-3.0/light/thumbnail.png
similarity index 100%
rename from common/gtk-3.0/thumbnail.png
rename to common/gtk-3.0/light/thumbnail.png
diff --git a/common/index.theme-dark b/common/index/dark/index.theme
similarity index 100%
rename from common/index.theme-dark
rename to common/index/dark/index.theme
diff --git a/common/index.theme-darker b/common/index/darker/index.theme
similarity index 100%
rename from common/index.theme-darker
rename to common/index/darker/index.theme
diff --git a/common/index.theme b/common/index/light/index.theme
similarity index 100%
rename from common/index.theme
rename to common/index/light/index.theme
diff --git a/common/xfwm4/Makefile.am b/common/xfwm4/Makefile.am
new file mode 100644
index 0000000..d9fc77a
--- /dev/null
+++ b/common/xfwm4/Makefile.am
@@ -0,0 +1,43 @@
+VPATH =
+
+targets := $(shell cat $(srcdir)/assets.txt)
+light := $(patsubst %,light/assets/%.png,$(targets))
+dark := $(patsubst %,dark/assets/%.png,$(targets))
+
+light: $(light)
+dark: $(dark)
+
+light/assets dark/assets:
+	$(MKDIR_P) "$@"/
+
+clean:
+	rm -rf light/assets/ dark/assets/
+
+$(light): $(srcdir)/light/assets.svg | light/assets
+$(dark): $(srcdir)/dark/assets.svg | dark/assets
+
+$(light) $(dark):
+	$(INKSCAPE) --export-id-only --export-png="$@" --export-id="$(basename $(notdir $@))" --export-dpi=$(if $(filter $(OPTION_GTK2_HIDPI),true),192,96) "$<" >/dev/null
+	$(OPTIPNG) -o7 --quiet "$@"
+
+.PHONY: light dark clean
+
+if ENABLE_LIGHT
+xfwm4themedir = $(themedir)/xfwm4
+xfwm4theme_DATA = $(srcdir)/light/themerc $(light)
+endif
+
+if ENABLE_DARKER
+xfwm4themedarkerdir = $(themedarkerdir)/xfwm4
+xfwm4themedarker_DATA = $(srcdir)/dark/themerc $(dark)
+endif
+
+if ENABLE_DARK
+xfwm4themedarkdir = $(themedarkdir)/xfwm4
+xfwm4themedark_DATA = $(srcdir)/dark/themerc $(dark)
+endif
+
+EXTRA_DIST = \
+	assets.txt \
+	$(patsubst %,%/assets.svg,light dark) \
+	$(patsubst %,%/themerc,light dark)
diff --git a/common/xfwm4/assets-dark.svg b/common/xfwm4/dark/assets.svg
similarity index 100%
rename from common/xfwm4/assets-dark.svg
rename to common/xfwm4/dark/assets.svg
diff --git a/common/xfwm4/themerc-dark b/common/xfwm4/dark/themerc
similarity index 100%
rename from common/xfwm4/themerc-dark
rename to common/xfwm4/dark/themerc
diff --git a/common/xfwm4/assets.svg b/common/xfwm4/light/assets.svg
similarity index 100%
rename from common/xfwm4/assets.svg
rename to common/xfwm4/light/assets.svg
diff --git a/common/xfwm4/themerc b/common/xfwm4/light/themerc
similarity index 100%
rename from common/xfwm4/themerc
rename to common/xfwm4/light/themerc
diff --git a/common/xfwm4/render-asset.sh b/common/xfwm4/render-asset.sh
deleted file mode 100755
index 590d3d1..0000000
--- a/common/xfwm4/render-asset.sh
+++ /dev/null
@@ -1,29 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-INKSCAPE="$(which inkscape)"
-OPTIPNG="$(which optipng)"
-
-ASSETS_DIR="$1"
-SRC_FILE="${ASSETS_DIR}".svg
-
-i="$2"
-
-
-result_file="$ASSETS_DIR/$i.png"
-if [[ -f "${result_file}" ]] ; then
-	echo "${result_file} already exists."
-else
-	echo "Rendering '${result_file}'"
-	if [[ "${OPTION_GTK2_HIDPI:-false}" != "true" ]]; then
-		"$INKSCAPE" --export-id="$i" \
-					--export-id-only \
-					--export-png="${result_file}" "$SRC_FILE" >/dev/null
-	else
-		"$INKSCAPE" --export-id="$i" \
-					--export-id-only \
-					--export-dpi=192 \
-					--export-png="${result_file}" "$SRC_FILE" >/dev/null
-	fi
-	"$OPTIPNG" -o7 --quiet "${result_file}"
-fi
diff --git a/common/xfwm4/render-assets.sh b/common/xfwm4/render-assets.sh
deleted file mode 100755
index 1509033..0000000
--- a/common/xfwm4/render-assets.sh
+++ /dev/null
@@ -1,13 +0,0 @@
-#!/bin/bash
-set -ueo pipefail
-
-# Make sure that parallel is GNU parallel and not moreutils.
-# Otherwise, it fails silently. There's no smooth way to detect this.
-if [[ "$(which parallel 2> /dev/null)" ]]; then
-  cmd=(parallel)
-else
-  cmd=(xargs -n1)
-fi
-
-"${cmd[@]}" ./render-asset.sh assets < assets.txt
-"${cmd[@]}" ./render-asset.sh assets-dark < assets.txt
diff --git a/configure.ac b/configure.ac
index 4473944..86fa6e9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,10 +26,37 @@ ARC_ENABLE([TRANSPARENCY],  [transparency],  [transparency],  [disable])
 ARC_ENABLE([PLANK],         [plank],         [Plank theme],   [disable])
 ARC_ENABLE([OPENBOX],       [openbox],       [Openbox],       [disable])
 
+AS_IF([test "x$ENABLE_TRANSPARENCY" != xno], [
+    AC_SUBST([themedir], [${datadir}/themes/Arc])
+    AC_SUBST([themedarkerdir], [${datadir}/themes/Arc-Darker])
+    AC_SUBST([themedarkdir], [${datadir}/themes/Arc-Dark])
+], [
+    AC_SUBST([themedir], [${datadir}/themes/Arc-solid])
+    AC_SUBST([themedarkerdir], [${datadir}/themes/Arc-Darker-solid])
+    AC_SUBST([themedarkdir], [${datadir}/themes/Arc-Dark-solid])
+])
+
 AS_IF([test "x$ENABLE_GTK3" != xno], [ARC_GTK3])
 AS_IF([test "x$ENABLE_GNOME_SHELL" != xno], [ARC_GNOME_SHELL])
 
+AS_IF([test "x$ENABLE_GTK2" != xno -o "x$ENABLE_GTK3" != xno -o "x$ENABLE_XFWM" != xno], [
+    AC_PATH_PROG([INKSCAPE], [inkscape])
+    AS_IF([test "x$ac_cv_path_INKSCAPE" = x], [AC_MSG_ERROR([inkscape not found])])
+    AC_PATH_PROG([OPTIPNG], [optipng])
+    AS_IF([test "x$ac_cv_path_OPTIPNG" = x], [AC_MSG_ERROR([optipng not found])])
+])
+
+AS_IF([test "x$ENABLE_GTK3" != xno -o "x$ENABLE_CINNAMON" != xno -o "x$ENABLE_GNOME_SHELL" != xno], [
+    AC_PATH_PROG([SASSC], [sassc])
+    AS_IF([test "x$ac_cv_path_SASSC" = x], [AC_MSG_ERROR([sassc not found])])
+])
+
 AC_CONFIG_FILES([
+    common/gtk-2.0/Makefile
+    common/gtk-3.0/Makefile
+    common/gtk-3.0/3.18/Makefile
+    common/gtk-3.0/3.20/Makefile
+    common/xfwm4/Makefile
     common/Makefile
     extra/Makefile
     Makefile
diff --git a/extra/Makefile.am b/extra/Makefile.am
index 2c06227..3007887 100644
--- a/extra/Makefile.am
+++ b/extra/Makefile.am
@@ -1,13 +1,3 @@
-if !ENABLE_TRANSPARENCY
-themedir        = $(datadir)/themes/Arc-solid
-themedarkerdir  = $(datadir)/themes/Arc-Darker-solid
-themedarkdir    = $(datadir)/themes/Arc-Dark-solid
-else
-themedir        = $(datadir)/themes/Arc
-themedarkerdir  = $(datadir)/themes/Arc-Darker
-themedarkdir    = $(datadir)/themes/Arc-Dark
-endif
-
 ithemedir       = $(DESTDIR)$(themedir)
 ithemedarkerdir = $(DESTDIR)$(themedarkerdir)
 ithemedarkdir   = $(DESTDIR)$(themedarkdir)
@@ -39,4 +29,5 @@ endif # ENABLE_PLANK
 uninstall-local:
 
 
-EXTRA_DIST = $(srcdir)/Arc-Plank
+EXTRA_DIST = \
+	Arc-Plank
diff --git a/m4/arc-gtk3.m4 b/m4/arc-gtk3.m4
index 0612543..bf656b7 100644
--- a/m4/arc-gtk3.m4
+++ b/m4/arc-gtk3.m4
@@ -24,15 +24,16 @@ AC_DEFUN([ARC_GTK3], [
     GTK3_VERSMJR=`echo $GTK3_VERSION | cut -d. -f1`
     GTK3_VERSMNR=`echo $GTK3_VERSION | cut -d. -f2`
 
-    # Evenize the minor version for stable versions
     AS_IF(
-        [test `expr $GTK3_VERSMNR % 2` != "0"],
-        [GTK3_VERSION="$GTK3_VERSMJR.`expr $GTK3_VERSMNR + 1`"]
-    )
-    AS_IF(
-        [! test -e "$GTK3DIR/$GTK3_VERSION"],
-        [AC_MSG_ERROR([Invalid GTK3 version: $GTK3_VERSION])]
+        [test "x$GTK3_VERSMJR" != x3], [AC_MSG_ERROR([Invalid GTK3 version: $GTK3_VERSION])],
+        [test "0$GTK3_VERSMNR" -lt 17], [AC_MSG_ERROR([GTK3 version too old: $GTK3_VERSION])],
+        [test "0$GTK3_VERSMNR" -lt 19], [GTK3_VERSION=3.18],
+        [test "0$GTK3_VERSMNR" -lt 25], [GTK3_VERSION=3.20],
+        [AC_MSG_ERROR([GTK3 version too new: $GTK3_VERSION])]
     )
     AC_SUBST([GTK3_VERSION])
+    AC_SUBST([gtk3themedir], [${themedir}/gtk-3.0])
+    AC_SUBST([gtk3themedarkerdir], [${themedarkerdir}/gtk-3.0])
+    AC_SUBST([gtk3themedarkdir], [${themedarkdir}/gtk-3.0])
     AC_MSG_RESULT([Building for GTK3 $GTK3_VERSION])
 ])