Fix doc

Author: JE-Chen

.readthedocs.yaml

@@ -1,9 +1,27 @@
-version: 2
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
 
-sphinx:
-  configuration: docs/source/conf.py
+# Required
+version: 2
 
+# Set the OS, Python version and other tools you might need
 build:
   os: ubuntu-22.04
   tools:
     python: "3.11"
+
+# Build documentation in the "docs/" directory with Sphinx
+sphinx:
+   configuration: docs/source/conf.py
+
+# Optionally build your docs in additional formats such as PDF and ePub
+formats:
+  - pdf
+  - epub
+
+# Optional but recommended, declare the Python requirements required
+# to build your documentation
+python:
+  install:
+  - requirements: docs/requirements.txt

docs/requirements.txt

@@ -0,0 +1 @@
+sphinx-rtd-theme