diff --git a/custom.scss b/custom.scss
index f41e658..8bb1c1f 100644
--- a/custom.scss
+++ b/custom.scss
@@ -157,9 +157,17 @@ pre:not(.sourceCode) {
         background: var(--bs-body-bg);
         font-family: sans-serif;
         font-weight: 600;
+    }
+
+    .cell-output-stdout &:before {
         content: " Output ";
     }
 
+    .cell-output-stderr &:before {
+        content: " Warning/Error ";
+        color: var(--quarto-scss-export-syndemics-pink);
+    }
+
     & code {
         margin-top: -1.2em;
         margin-left: 0.5em;