diff --git a/meson.build b/meson.build
index e22a4fc1..b20af991 100644
--- a/meson.build
+++ b/meson.build
@@ -6,14 +6,43 @@ project('adwcustomizer',
                    ],
 )
 
-dependency('glib-2.0')
-dependency('pygobject-3.0')
-dependency('libadwaita-1')
-
-i18n = import('i18n')
-
+# Import modules
 gnome = import('gnome')
+i18n = import('i18n')
+python = import('python')
 
+# Constants
+PROJECT_RDNN_NAME = 'com.github.AdwCustomizerTeam.AdwCustomizer'
+APPLICATION_ID = PROJECT_RDNN_NAME
+
+dependency('glib-2.0')
+dependency('gtk4', version: '>= 4.5.0')
+dependency('libadwaita-1', version: '>= 1.2.alpha')
+dependency('pygobject-3.0', version: '>= 3.42.0')
+
+# Python installation directory
+PY_INSTALLDIR = python.find_installation('python3')
+
+# Check if python3 is installed
+if not PY_INSTALLDIR.found()
+    error('No valid python3 binary found')
+endif
+
+PKGDATA_DIR = join_paths(get_option('prefix'), get_option('datadir'), meson.project_name())
+MODULE_DIR = join_paths(PKGDATA_DIR, 'adwcustomizer')
+PLUGINS_DIR = join_paths(PKGDATA_DIR, 'adwcustomizer', 'plugins')
+
+# Install configuration data
+conf = configuration_data()
+conf.set('APP_ID', PROJECT_RDNN_NAME)
+conf.set('PKGDATA_DIR', PKGDATA_DIR)
+conf.set('DATA_DIR', join_paths(get_option('prefix'), get_option('datadir')))
+conf.set('LOCALE_DIR', join_paths(get_option('prefix'), get_option('localedir')))
+conf.set('PYTHON', PY_INSTALLDIR.full_path())
+conf.set('VERSION', meson.project_version())
+conf.set('BUILD_TYPE', get_option('buildtype'))
+
+# Subdirs
 subdir('data')
 subdir('src')
 subdir('po')
diff --git a/src/adwcustomizer.in b/src/adwcustomizer.in
index 7f88fc5f..14610ac8 100755
--- a/src/adwcustomizer.in
+++ b/src/adwcustomizer.in
@@ -24,15 +24,17 @@ import signal
 import locale
 import gettext
 
-VERSION = '@VERSION@'
-pkgdatadir = '@pkgdatadir@'
-localedir = '@localedir@'
+pkgdatadir = '@PKGDATA_DIR@'
+localedir = '@LOCALE_DIR@'
+version = '@VERSION@'
 
 sys.path.insert(1, pkgdatadir)
 signal.signal(signal.SIGINT, signal.SIG_DFL)
+gettext.install('adwcustomizer', localedir)
+
 locale.bindtextdomain('adwcustomizer', localedir)
 locale.textdomain('adwcustomizer')
-gettext.install('adwcustomizer', localedir)
+
 
 if __name__ == '__main__':
     import gi
@@ -43,8 +45,9 @@ if __name__ == '__main__':
     gi.require_version('XdpGtk4', '1.0')
 
     from gi.repository import Gio
-    resource = Gio.Resource.load(os.path.join(pkgdatadir, 'adwcustomizer.gresource'))
+    resource = Gio.Resource.load(
+        os.path.join(pkgdatadir, 'adwcustomizer.gresource'))
     resource._register()
 
     from adwcustomizer import main
-    sys.exit(main.main(VERSION))
+    sys.exit(main.main(version))
diff --git a/src/app_type_dialog.py b/src/app_type_dialog.py
index f7f88133..600d9452 100644
--- a/src/app_type_dialog.py
+++ b/src/app_type_dialog.py
@@ -18,10 +18,10 @@
 
 from gi.repository import Gtk, Adw
 
+from .constants import rootdir
 
-@Gtk.Template(
-    resource_path="/com/github/AdwCustomizerTeam/AdwCustomizer/ui/app_type_dialog.ui"
-)
+
+@Gtk.Template(resource_path=f"{rootdir}/ui/app_type_dialog.ui")
 class AdwcustomizerAppTypeDialog(Adw.MessageDialog):
     __gtype_name__ = "AdwcustomizerAppTypeDialog"
 
diff --git a/src/constants.py.in b/src/constants.py.in
new file mode 100644
index 00000000..67eb90c7
--- /dev/null
+++ b/src/constants.py.in
@@ -0,0 +1,4 @@
+rootdir          = '/com/github/AdwCustomizerTeam/AdwCustomizer'
+app_id           = '@APP_ID@'
+version          = '@VERSION@'
+build_type       = '@BUILD_TYPE@'
\ No newline at end of file
diff --git a/src/custom_css_group.py b/src/custom_css_group.py
index 1f98ab80..d241fbc3 100644
--- a/src/custom_css_group.py
+++ b/src/custom_css_group.py
@@ -18,10 +18,10 @@
 
 from gi.repository import Gtk, Adw
 
+from .constants import rootdir
 
-@Gtk.Template(
-    resource_path="/com/github/AdwCustomizerTeam/AdwCustomizer/ui/custom_css_group.ui"
-)
+
+@Gtk.Template(resource_path=f"{rootdir}/ui/custom_css_group.ui")
 class AdwcustomizerCustomCSSGroup(Adw.PreferencesGroup):
     __gtype_name__ = "AdwcustomizerCustomCSSGroup"
 
diff --git a/src/error.py b/src/error.py
index 2760bd54..8c87839e 100644
--- a/src/error.py
+++ b/src/error.py
@@ -18,8 +18,10 @@
 
 from gi.repository import Gtk
 
+from .constants import rootdir
 
-@Gtk.Template(resource_path="/com/github/AdwCustomizerTeam/AdwCustomizer/ui/error.ui")
+
+@Gtk.Template(resource_path=f"{rootdir}/ui/error.ui")
 class AdwcustomizerError(Gtk.ListBoxRow):
     __gtype_name__ = "AdwcustomizerError"
 
diff --git a/src/info.py.in b/src/info.py.in
deleted file mode 100644
index 20fc3494..00000000
--- a/src/info.py.in
+++ /dev/null
@@ -1,2 +0,0 @@
-version          = '@version@'
-build_type       = '@build_type@'
\ No newline at end of file
diff --git a/src/main.py b/src/main.py
index acd4983c..f572e6ac 100644
--- a/src/main.py
+++ b/src/main.py
@@ -35,7 +35,7 @@ from .option import AdwcustomizerOption
 from .app_type_dialog import AdwcustomizerAppTypeDialog
 from .custom_css_group import AdwcustomizerCustomCSSGroup
 from .plugins_list import AdwcustomizerPluginsList
-from . import info
+from .constants import rootdir, app_id, version
 
 
 def to_slug_case(non_slug):
@@ -47,7 +47,7 @@ class AdwcustomizerApplication(Adw.Application):
 
     def __init__(self, version):
         super().__init__(
-            application_id="com.github.AdwCustomizerTeam.AdwCustomizer",
+            application_id=app_id,
             flags=Gio.ApplicationFlags.FLAGS_NONE,
         )
         self.version = version
@@ -100,11 +100,11 @@ class AdwcustomizerApplication(Adw.Application):
         self.style_manager = Adw.StyleManager.get_default()
         if self.style_manager.get_dark():
             self.load_preset_from_resource(
-                "/com/github/AdwCustomizerTeam/AdwCustomizer/presets/adwaita-dark.json"
+                f"{rootdir}/presets/adwaita-dark.json"
             )
         else:
             self.load_preset_from_resource(
-                "/com/github/AdwCustomizerTeam/AdwCustomizer/presets/adwaita.json"
+                f"{rootdir}/presets/adwaita.json"
             )
 
         self.win.present()
@@ -412,7 +412,7 @@ class AdwcustomizerApplication(Adw.Application):
             )
         else:
             self.load_preset_from_resource(
-                "/com/github/AdwCustomizerTeam/AdwCustomizer/presets/"
+                f"{rootdir}/presets/"
                 + args[0].get_string()
                 + ".json"
             )
@@ -665,7 +665,7 @@ class AdwcustomizerApplication(Adw.Application):
                 Taylan Tatlı https://www.transifex.com/user/profile/TaylanTatli34/""",
             copyright="© 2022 Adwaita Manager Team",
             license_type=Gtk.License.GPL_3_0,
-            version=f"{info.version}",
+            version=f"{version}",
             release_notes="""
                 <ul>
         <li>Add AdwViewSwitcher in the header bar.</li>
diff --git a/src/meson.build b/src/meson.build
index d3e13293..c3e04714 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1,6 +1,3 @@
-pkgdatadir = join_paths(get_option('prefix'), get_option('datadir'), meson.project_name())
-moduledir = join_paths(pkgdatadir, 'adwcustomizer')
-pluginsdir = join_paths(pkgdatadir, 'adwcustomizer', 'plugins')
 gnome = import('gnome')
 
 blueprints = custom_target('blueprints',
@@ -20,18 +17,10 @@ gnome.compile_resources('adwcustomizer',
   'adwcustomizer.gresource.xml',
   gresource_bundle: true,
   install: true,
-  install_dir: pkgdatadir,
+  install_dir: PKGDATA_DIR,
   dependencies: blueprints,
 )
 
-python = import('python')
-
-conf = configuration_data()
-conf.set('PYTHON', python.find_installation('python3').full_path())
-conf.set('VERSION', meson.project_version())
-conf.set('localedir', join_paths(get_option('prefix'), get_option('localedir')))
-conf.set('pkgdatadir', pkgdatadir)
-
 configure_file(
   input: 'adwcustomizer.in',
   output: 'adwcustomizer',
@@ -41,16 +30,14 @@ configure_file(
 )
 
 configure_file(
-          input: 'info.py.in',
-         output: '@BASENAME@',
-        install: true,
-    install_dir: moduledir,
-  configuration: configuration_data({
-           'version': meson.project_version(),
-        'build_type': get_option('buildtype'),
-  }),
+  input: 'constants.py.in',
+  output: 'constants.py',
+  configuration: conf,
+  install: true,
+  install_dir: MODULE_DIR
 )
 
+# Install sources
 adwcustomizer_sources = [
   '__init__.py',
   'settings_schema.py',
@@ -65,11 +52,10 @@ adwcustomizer_sources = [
   'app_type_dialog.py',
   'custom_css_group.py',
 ]
+install_data(adwcustomizer_sources, install_dir: MODULE_DIR)
 
 plugins_sources = [
   'plugins/__init__.py',
   'plugins/gtk4.py'
 ]
-
-install_data(adwcustomizer_sources, install_dir: moduledir)
-install_data(plugins_sources, install_dir: pluginsdir)
\ No newline at end of file
+install_data(plugins_sources, install_dir: PLUGINS_DIR)
\ No newline at end of file
diff --git a/src/option.py b/src/option.py
index 885339f2..763303ac 100644
--- a/src/option.py
+++ b/src/option.py
@@ -18,8 +18,10 @@
 
 from gi.repository import Gtk, Gdk, Adw
 
+from .constants import rootdir
 
-@Gtk.Template(resource_path="/com/github/AdwCustomizerTeam/AdwCustomizer/ui/option.ui")
+
+@Gtk.Template(resource_path=f"{rootdir}/ui/option.ui")
 class AdwcustomizerOption(Adw.ActionRow):
     __gtype_name__ = "AdwcustomizerOption"
 
diff --git a/src/palette_shades.py b/src/palette_shades.py
index dcb0cc63..1411f0dd 100644
--- a/src/palette_shades.py
+++ b/src/palette_shades.py
@@ -18,10 +18,10 @@
 
 from gi.repository import Gtk, Gdk, Adw
 
+from .constants import rootdir
 
-@Gtk.Template(
-    resource_path="/com/github/AdwCustomizerTeam/AdwCustomizer/ui/palette_shades.ui"
-)
+
+@Gtk.Template(resource_path=f"{rootdir}/ui/palette_shades.ui")
 class AdwcustomizerPaletteShades(Adw.ActionRow):
     __gtype_name__ = "AdwcustomizerPaletteShades"
 
diff --git a/src/window.py b/src/window.py
index 2e35d7f4..9dd85bb9 100644
--- a/src/window.py
+++ b/src/window.py
@@ -34,9 +34,10 @@ from .option import AdwcustomizerOption
 from .app_type_dialog import AdwcustomizerAppTypeDialog
 from .custom_css_group import AdwcustomizerCustomCSSGroup
 from material_color_utilities_python import *
+from .constants import rootdir, build_type
 
 
-@Gtk.Template(resource_path="/com/github/AdwCustomizerTeam/AdwCustomizer/ui/window.ui")
+@Gtk.Template(resource_path=f"{rootdir}/ui/window.ui")
 class AdwcustomizerMainWindow(Adw.ApplicationWindow):
     __gtype_name__ = "AdwcustomizerMainWindow"
 
@@ -57,6 +58,10 @@ class AdwcustomizerMainWindow(Adw.ApplicationWindow):
             "show", self.on_presets_dropdown_activate
         )
 
+        # Set devel style
+        if build_type == "debug":
+            self.get_style_context().add_class("devel")
+
         self.setup_monet_page()
         self.setup_plugins_page()
         self.setup_colors_page()