Setting "codemirror-theme" doesn't work

Describe the bug

When I set a codemirror theme, it doesn't seem to change anything; the colors remain the default.

I tried adding this to conf.py, as instructed at https://sphinx-thebe.readthedocs.io/en/latest/configure.html#choose-a-codemirror-theme:

thebe_config = {
   "codemirror-theme": "dracula"
}

Out of desperation, and in case there was an error in the documentation, I even tried this:

thebe_config = {
    "codeMirrorConfig": {
        "codemirror-theme": "dracula",
        "codemirror_theme": "yeti"
    },
    "codemirror-theme": "ayu-dark",
    "codemirror_theme": "cobalt"
}

codemirror_theme = "colorforth"

codeMirrorConfig = {
    "codemirror-theme": "hopscotch",
    "codemirror_theme": "liquibyte"
}

None of them worked.

Reproduce the bug

Add

thebe_config = {
"codemirror-theme": "dracula"
}

to your conf.py file

Build your documentation
Open your documentation and see that the colors have not changed

List your environment

Package Version

alabaster 0.7.13
anyio 3.6.2
apeye 1.3.0
apeye-core 1.1.1
appdirs 1.4.4
argon2-cffi 21.3.0
argon2-cffi-bindings 21.2.0
arrow 1.2.3
asttokens 2.2.1
attrs 22.2.0
autodoc 0.5.0
autodocsumm 0.2.10
Babel 2.11.0
backcall 0.2.0
beautifulsoup4 4.11.2
bleach 6.0.0 CacheControl 0.12.11 certifi 2022.12.7 cffi 1.15.1 charset-normalizer 3.0.1 click 8.1.3 colorama 0.4.6 comm 0.1.2 contourpy 1.0.7 cssutils 2.6.0 cycler 0.11.0 datagen-tech 1.4.14 debugpy 1.6.6 decorator 5.1.1 defusedxml 0.7.1 dependency-injector 4.41.0 dict2css 0.3.0 docutils 0.19 domdf-python-tools 3.6.0 dynaconf 3.1.11 executing 1.2.0 fastjsonschema 2.16.2 fonttools 4.38.0 fqdn 1.5.1 furo 2022.12.7 greenlet 2.0.2 html5lib 1.1 idna 3.4 imagesize 1.4.1 importlib-metadata 4.13.0 ipykernel 6.21.1 ipython 8.10.0 ipython-genutils 0.2.0 ipywidgets 8.0.4 isoduration 20.11.0 jedi 0.18.2 Jinja2 3.0.3 jsonpointer 2.3 jsonschema 4.17.3 jupyter 1.0.0 jupyter-cache 0.5.0 jupyter_client 8.0.2 jupyter-console 6.5.0 jupyter_core 5.2.0 jupyter-events 0.6.3 jupyter_server 2.2.1 jupyter_server_terminals 0.4.4 jupyterlab-pygments 0.2.2 jupyterlab-widgets 3.0.5 kiwisolver 1.4.4 lockfile 0.12.2 markdown-it-py 2.1.0 MarkupSafe 2.1.2 marshmallow 3.19.0 marshmallow-dataclass 8.5.11 marshmallow-enum 1.5.1 matplotlib 3.7.0 matplotlib-inline 0.1.6 mdit-py-plugins 0.3.3 mdurl 0.1.1 mistune 2.0.5 msgpack 1.0.4 mypy-extensions 1.0.0 myst-nb 0.17.1 myst-parser 0.18.1 natsort 8.2.0 nbclassic 0.5.1 nbclient 0.5.13 nbconvert 7.2.9 nbformat 5.7.3 nest-asyncio 1.5.6 notebook 6.5.2 notebook_shim 0.2.2 numpy 1.24.2 opencv-python 4.7.0.68 packaging 23.0 pandas 1.5.3 pandocfilters 1.5.0 parso 0.8.3 pickleshare 0.7.5 Pillow 9.4.0 pip 23.0.1 platformdirs 3.0.0 prometheus-client 0.16.0 prompt-toolkit 3.0.36 psutil 5.9.4 pure-eval 0.2.2 pycparser 2.21 pydantic 1.10.4 pydata-sphinx-theme 0.8.1 Pygments 2.14.0 pyparsing 3.0.9 pyrsistent 0.19.3 python-dateutil 2.8.2 python-json-logger 2.0.4 pytz 2022.7.1 pywin32 305 pywinpty 2.0.10 PyYAML 6.0 pyzmq 25.0.0 qtconsole 5.4.0 QtPy 2.3.0 requests 2.28.2 rfc3339-validator 0.1.4 rfc3986-validator 0.1.1 rich 13.3.1 ruamel.yaml 0.17.21 scipy 1.10.0 Send2Trash 1.8.0 setuptools 65.5.0 six 1.16.0 sniffio 1.3.0 snowballstemmer 2.2.0 soupsieve 2.3.2.post1 Sphinx 6.1.3 sphinx-autodoc-typehints 1.19.1 sphinx-basic-ng 1.0.0b1 sphinx-book-theme 0.3.3 sphinx-copybutton 0.5.1 sphinx_design 0.3.0 sphinx-jinja2-compat 0.2.0 sphinx-prompt 1.5.0 sphinx-rtd-theme 1.2.0 sphinx-tabs 3.4.0 sphinx-thebe 0.2.1 sphinx-toolbox 3.4.0 sphinxcontrib-applehelp 1.0.4 sphinxcontrib-devhelp 1.0.2 sphinxcontrib-htmlhelp 2.0.1 sphinxcontrib-jquery 2.0.0 sphinxcontrib-jsmath 1.0.1 sphinxcontrib-qthelp 1.0.3 sphinxcontrib-serializinghtml 1.1.5 sphinxemoji 0.2.0 sphinxext-opengraph 0.8.1 SQLAlchemy 1.4.46 stack-data 0.6.2 tabulate 0.9.0 terminado 0.17.1 tinycss2 1.2.1 tornado 6.2 traitlets 5.9.0 typing_extensions 4.2.0 typing-inspect 0.8.0 uri-template 1.2.0 urllib3 1.26.14 waitress 2.1.2 wcwidth 0.2.6 webcolors 1.12 webencodings 0.5.1 WebOb 1.8.7 websocket-client 1.5.1 WebTest 3.0.0 widgetsnbextension 4.0.5 zipp 3.13.0

executablebooks / sphinx-thebe