diff --git a/docs/conf.py b/docs/conf.py
index 66e3471..1932813 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -35,8 +35,11 @@
     "sphinx.ext.intersphinx",
     "sphinx.ext.napoleon",
     "sphinx.ext.viewcode",
+    "sphinx_rtd_theme",
 ]
 
+html_theme = "sphinx_rtd_theme"
+
 autosectionlabel_prefix_document = True
 
 intersphinx_mapping = {
diff --git a/pyproject.toml b/pyproject.toml
index b13162c..a1dbc81 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -69,7 +69,8 @@ dependencies = [
 [project.optional-dependencies]
 
 docs = [
-    "sphinx"
+    "sphinx",
+    "sphinx-rtd-theme",
 ]
 testing = [
     "packaging",  # A test case uses packaging.version.Version