diff --git a/static/colors.css b/static/colors.css
index 9ceb9f37..6a9c5c70 100644
--- a/static/colors.css
+++ b/static/colors.css
@@ -40,6 +40,8 @@
     --alert-important: #ff8ffd;
     --alert-warning: #ffaf00;
     --alert-caution: #ff5f5f;
+
+    --ipynb-bg-error: rgba(255, 0, 0, 0.1);
 }
 
 /* --------------------------------------------------------------------------
@@ -89,5 +91,6 @@
         --alert-warning: #bf8700;
         --alert-caution: #cf222e;
 
+        --ipynb-bg-error: rgba(255, 0, 0, 0.1);
     }
 }
diff --git a/static/ipynb.css b/static/ipynb.css
index 57911b9b..e68d9702 100644
--- a/static/ipynb.css
+++ b/static/ipynb.css
@@ -19,9 +19,9 @@
     padding: unset;
     background-color: unset;
 }
-.ipynb-output-stream-stderr { background-color: rgba(255, 0, 0, 0.1); }
+.ipynb-output-stream-stderr { background-color: var(--ipynb-bg-error); }
 
-.ipynb-output-error { background-color: rgba(255, 0, 0, 0.1); }
+.ipynb-output-error { background-color: var(--ipynb-bg-error); }
 
 .ipynb-output-plain {
     padding: unset;