Update app.py

app.py

@@ -118,11 +118,11 @@ index_html = """
         }
 
         function syncWidth(value) {
-            document.getElementById("width").value = value;
+            document.getElementById("width-slider").value = value;
         }
 
         function syncHeight(value) {
-            document.getElementById("height").value = value;
+            document.getElementById("height-slider").value = value;
         }
 
         function updateWidthInput() {