diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 0f5d6fd..4ade908 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest          # picks ubuntu:latest via runner labels
     # OR override with any image:
     container:
-      image: python:3.12-slim       # runner spawns this exact image
+      image: ubuntu-latest       # runner spawns this exact image
     steps:
       - uses: actions/checkout@v4
       - run: python --version