Fix UI crash in index.html by guarding outputEmpty element references

index.html

@@ -633,7 +633,7 @@
             previewVideo.src = "";
             previewVideo.classList.add("hidden");
             uploadPrompt.classList.remove("hidden");
-            outputEmpty.classList.remove("hidden");
+            if (outputEmpty) outputEmpty.classList.remove("hidden");
             outputImage.src = "";
             outputImage.classList.add("hidden");
             outputVideo.src = "";
@@ -775,7 +775,7 @@
             processingStatus.textContent = "Waiting for Gradio queue...";
             
             // Clean outputs
-            outputEmpty.classList.add("hidden");
+            if (outputEmpty) outputEmpty.classList.add("hidden");
             outputImage.classList.add("hidden");
             outputVideo.classList.add("hidden");
             richTraceLog.innerHTML = "";
@@ -885,7 +885,7 @@
                 metaStatus.className = "text-red-500 font-semibold";
                 detectionTagsWrapper.innerHTML = `<span class="text-red-400">Failed: ${err.message}</span>`;
                 alert(`Inference failed: ${err.message}`);
-                outputEmpty.classList.remove("hidden");
+                if (outputEmpty) outputEmpty.classList.remove("hidden");
             } finally {
                 // Restore UI state
                 runBtn.disabled = false;