diff --git a/.github/workflows/sphinx.yml b/.github/workflows/sphinx.yml
index db4afd8..1a8f376 100644
--- a/.github/workflows/sphinx.yml
+++ b/.github/workflows/sphinx.yml
@@ -16,7 +16,9 @@ jobs:
     - name: Install dependencies
       run: conda install -y sphinx_rtd_theme
     - name: Build HTML
-      uses: ammaraskar/sphinx-action@master
+    - uses: ammaraskar/sphinx-action@master
+      with:
+        pre-build-command: "conda install -y sphinx_rtd_theme"
     - name: Upload artifacts
       uses: actions/upload-artifact@v4
       with: