diff --git a/cmake/Docs.cmake b/cmake/Docs.cmake
index 93333da02..4bb942a76 100644
--- a/cmake/Docs.cmake
+++ b/cmake/Docs.cmake
@@ -16,7 +16,9 @@ SET(SPHINX_MANPAGE_DIR "${SPHINX_ROOT_DIR}/man")
 # sphinx-docs uses fish_indent for highlighting.
 # Prepend the output dir of fish_indent to PATH.
 ADD_CUSTOM_TARGET(sphinx-docs
-    env PATH="$<TARGET_FILE_DIR:fish_indent>:$$PATH"
+    ${CMAKE_COMMAND} -E copy_if_different ${SPHINX_SRC_DIR}/_static/pygments.css ${SPHINX_HTML_DIR}/_static/
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${SPHINX_SRC_DIR}/_static/custom.css ${SPHINX_HTML_DIR}/_static/
+    COMMAND env PATH="$<TARGET_FILE_DIR:fish_indent>:$$PATH"
         ${SPHINX_EXECUTABLE}
         -q -b html
         -c "${SPHINX_SRC_DIR}"
diff --git a/sphinx_doc_src/_static/custom.css b/sphinx_doc_src/_static/custom.css
index 29eb6b40b..b631991e3 100644
--- a/sphinx_doc_src/_static/custom.css
+++ b/sphinx_doc_src/_static/custom.css
@@ -1 +1 @@
-.sphinxsidebar > ul.current > li.current { font-weight: bold }
+.sphinxsidebar ul.current > li.current { font-weight: bold }