diff --git a/services/web/frontend/js/features/source-editor/languages/typst/index.ts b/services/web/frontend/js/features/source-editor/languages/typst/index.ts
index da826de772..508e94e7d7 100644
--- a/services/web/frontend/js/features/source-editor/languages/typst/index.ts
+++ b/services/web/frontend/js/features/source-editor/languages/typst/index.ts
@@ -101,6 +101,8 @@ const typstHighlightStyle = HighlightStyle.define([
   { tag: t.heading, fontWeight: 'bold' },
   { tag: t.strong, fontWeight: 'bold' },
   { tag: t.emphasis, fontStyle: 'italic' },
+  // Diagnostic: force arg keys bright red so we can confirm the token reaches the highlighter.
+  { tag: t.attributeName, color: '#cc0000', fontWeight: 'bold' },
 ])
 
 export const typst = () => {