diff --git a/poetry.lock b/poetry.lock
index 00c968d..8c56a2b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -4023,9 +4023,9 @@ docs = ["furo", "jaraco.packaging (>=9.3)", "jaraco.tidelift (>=1.4)", "rst.link
 testing = ["big-O", "jaraco.functools", "jaraco.itertools", "more-itertools", "pytest (>=6)", "pytest-black (>=0.3.7)", "pytest-checkdocs (>=2.4)", "pytest-cov", "pytest-enabler (>=2.2)", "pytest-ignore-flaky", "pytest-mypy (>=0.9.1)", "pytest-ruff"]
 
 [extras]
-docs = []
+docs = ["sphinx", "sphinx-copybutton", "sphinx-rtd-theme"]
 
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.9"
-content-hash = "0490f677eb41eac66256b2e82d75373754b1af00ab061ce68e78a509b01ce86f"
+content-hash = "91353e5ca366e34e70e64396cb7ecd99d5c5d5b9c544718e604c52535800fabb"
diff --git a/pyproject.toml b/pyproject.toml
index 2b4748a..b45d532 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,6 +16,9 @@ oaklib = "^0.5.13"
 matplotlib = "^3.7.2"
 pandasaurus = "^0.3.5"
 pygraphviz = "^1.11"
+sphinx = { version = "^7.2.6", optional = true }
+sphinx-rtd-theme = { version = "^1.3.0", optional = true }
+sphinx-copybutton = { version = "^0.5.2", optional = true }
 
 [tool.poetry.group.dev.dependencies]
 pytest = "^7.3.1"
@@ -26,9 +29,6 @@ flake8-black = "^0.3.6"
 flake8-isort = "^6.0.0"
 pytest-cov = "^4.1.0"
 pytest-mock = "^3.10.0"
-sphinx = { version = "^7.2.6", optional = true }
-sphinx-rtd-theme = { version = "^1.3.0", optional = true }
-sphinx-copybutton = { version = "^0.5.2", optional = true }
 
 [build-system]
 requires = ["poetry-core"]