diff --git a/SessionZero/Pages/SzfEditor.razor b/SessionZero/Pages/SzfEditor.razor
index e65c245..0fe2633 100644
--- a/SessionZero/Pages/SzfEditor.razor
+++ b/SessionZero/Pages/SzfEditor.razor
@@ -37,9 +37,9 @@
                               autocomplete="off"
                               @ref="textareaRef"></textarea>
                     <div class="syntax-overlay" @ref="overlayRef">
-                        @foreach (var line in _highlightedLines)
+                        @for (int i = 0; i < _highlightedLines.Count; i++)
                         {
-                            <div class="syntax-line">@((MarkupString)line)</div>
+                            <div class="syntax-line @(HasErrorOnLine(i) ? "error-underline" : "")">@((MarkupString)_highlightedLines[i])</div>
                         }
                     </div>
                 </div>
@@ -646,6 +646,11 @@ ArmorClass (calculated) = 10 + DexterityMod
         height: 21px;
     }
 
+    .syntax-line.error-underline {
+        text-decoration: underline wavy #ff5555;
+        text-decoration-skip-ink: none;
+    }
+
     /* SZF Syntax Highlighting */
     .cm-header { color: #61afef; }
     .cm-meta { color: #c678dd; }