docs: let's use the Read the Docs theme for Sphinx again

.github/workflows/doc.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Setup and build
         run: |
           sudo apt-get install python3-pip
-          pip3 install sphinx sphinx-vhdl sphinx_rtd_theme furo GitPython
+          pip3 install sphinx sphinx-vhdl sphinx_rtd_theme GitPython
           mkdir public
           mkdir public/html
           cp doc/source/index.html public/html/

.gitlab-ci.yml

@@ -16,7 +16,7 @@ pages:
     - apk add git
     - pip install -U GitPython
     - pip install -U sphinx
-    - pip install -U furo
+    - pip install -U sphinx-rtd-theme
     - pip install -U sphinx-vhdl
     - echo "Hotfix detached head, causing trouble in GitPython:"
     - git checkout $CI_COMMIT_BRANCH

README.md

@@ -60,7 +60,7 @@ First, you need to install a few Python packages:
 $ pip3 install --user GitPython
 $ pip3 install --user sphinx
 $ pip3 install --user sphinx-vhdl
-$ pip3 install --user furo
+$ pip3 install --user sphinx-rtd-theme
 ```
 
 Then the documentation is generated simply by issuing these two commands:

doc/source/conf.py

@@ -50,10 +50,13 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-html_theme = 'furo'
+html_theme = 'sphinx_rtd_theme'
 html_theme_options = {
-    "globaltoc_maxdepth": 4,
-    "banner_hiding": "permanent",
+    'collapse_navigation': True,
+    'sticky_navigation': True,
+    'navigation_depth': 4,
+    'includehidden': True,
+    'display_version': True,
 }
 
 html_logo = "img/ndk_fpga_logo_simple.png"
@@ -62,3 +65,5 @@
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
 html_static_path = ['_static']
+
+html_style = 'css/theme_overrides.css'