diff --git a/ntd2d/ntd2d_action/files/borgedconffile.py b/ntd2d/ntd2d_action/files/borgedconffile.py
index 05ff75e..a3d724b 100644
--- a/ntd2d/ntd2d_action/files/borgedconffile.py
+++ b/ntd2d/ntd2d_action/files/borgedconffile.py
@@ -5,9 +5,9 @@
 class BorgedConfFile(ConfFile):
     """Sphinx configuration file that overlays the html theme."""
 
-    def __init__(self, source_dir, original_docs):
+    def __init__(self, source_dir, config, original_docs):
         self.original_docs = original_docs
-        super().__init__(source_dir=source_dir)
+        super().__init__(source_dir=source_dir, config=config)
         self._html_theme = None
 
     @property
diff --git a/ntd2d/ntd2d_action/files/conffile.py b/ntd2d/ntd2d_action/files/conffile.py
index 8c1957e..791ba6b 100644
--- a/ntd2d/ntd2d_action/files/conffile.py
+++ b/ntd2d/ntd2d_action/files/conffile.py
@@ -22,23 +22,14 @@ def _working_directory(path):
 class ConfFile(File):
     """Sphinx configuration file."""
 
-    def __init__(self, source_dir):
+    def __init__(self, source_dir, config):
         self.source_dir = pathlib.Path(source_dir)
-        self.theme = None
+        self.config = config
         self._code = None
-        self._configuration = None
-
-    @property
-    def configuration(self):
-        """Text of configuration file."""
-
-        if self._configuration is None:
-            self._configuration = self.read()
-        return self._configuration
 
     @property
     def exclude_patterns(self):
-        return self.configuration.get("exclude_patterns", [])
+        return self.config.exclude_patterns
 
     @property
     def html_theme(self):
@@ -46,7 +37,7 @@ def html_theme(self):
 
         .. _html_theme: https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-html_theme
         """
-        return self.configuration.get("html_theme", "default")
+        return self.config.html_theme
 
     @property
     def html_theme_path(self):
@@ -54,7 +45,7 @@ def html_theme_path(self):
 
         .. _html_theme_path: https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-html_theme_path
         """
-        return self.configuration.get("html_theme_path", [])
+        return self.config.html_theme_path
 
     @property
     def language(self):
@@ -62,7 +53,7 @@ def language(self):
 
         .. _language: https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-language
         """
-        return self.configuration.get("language", "en")
+        return self.config.language
 
     @property
     def original_contents(self):
@@ -82,7 +73,7 @@ def project(self):
 
         .. _project: https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-project
         """
-        return self.configuration["project"]
+        return self.config.project
 
     @property
     def theme_path(self):
diff --git a/ntd2d/ntd2d_action/sphinxdocs.py b/ntd2d/ntd2d_action/sphinxdocs.py
index 69661c7..bbb25e1 100644
--- a/ntd2d/ntd2d_action/sphinxdocs.py
+++ b/ntd2d/ntd2d_action/sphinxdocs.py
@@ -22,6 +22,7 @@ class SphinxDocs:
     """Sphinx configuration directory."""
 
     def __init__(self, docs_dir):
+        self._app = None
         self.docs_dir = pathlib.Path(docs_dir)
 
         if (self.docs_dir / "source" / "conf.py").is_file():
@@ -34,7 +35,18 @@ def __init__(self, docs_dir):
         self.conf = self.make_conf_file()
 
     def make_conf_file(self):
-        return ConfFile(source_dir=self.source_dir)
+        return ConfFile(source_dir=self.source_dir,
+                        config=self.sphinx_app.config)
+
+    @property
+    def sphinx_app(self):
+        if self._app is None:
+            self._app = Sphinx(srcdir=self.source_dir,
+                               confdir=self.source_dir,
+                               outdir=self.build_dir,
+                               doctreedir=self.build_dir / "doctrees",
+                               buildername="html")
+        return self._app
 
     @property
     def html_dir(self):
@@ -50,13 +62,8 @@ def pdf_file(self):
 
     @property
     def stylesheet(self):
-        app = Sphinx(srcdir=self.source_dir,
-                     confdir=self.source_dir,
-                     outdir=self.build_dir,
-                     doctreedir=self.build_dir / "doctrees",
-                     buildername="html")
-        theme_factory = HTMLThemeFactory(app)
-        theme = theme_factory.create(app.config.html_theme)
+        theme_factory = HTMLThemeFactory(self.sphinx_app)
+        theme = theme_factory.create(self.sphinx_app.config.html_theme)
 
         return theme.get_config("theme", "stylesheet")
 
@@ -135,6 +142,7 @@ def __init__(self, original_docs):
 
     def make_conf_file(self):
         return BorgedConfFile(source_dir=self.source_dir,
+                              config=self.sphinx_app.config,
                               original_docs=self.original_docs)
 
     @property