diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 036d4015314231238ea665ba859524cdb931bf05..d6eb992204a1720e49a7064d18af31deb0b27e42 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -11,7 +11,7 @@ build:
     - sage -pip install "pseudowalls==0.0.3" --extra-index-url https://gitlab.com/api/v4/projects/43962374/packages/pypi/simple
     - make tilt.rs
     - latexmk -use-make
-    - sed -i -e '1s/^/\\def\\notebookappendix{}/' main.tex
+    - sed -i -e '1s/^/\\def\\notebookappendix{} /' main.tex
     - latexmk -use-make
   artifacts:
     paths: