ux: clear template comments on first keystroke via change handler

app.py

@@ -414,9 +414,33 @@ def build_app() -> gr.Blocks:
         # ---- State ----
         tier_idx_state = gr.State(value=0)
         lang_state = gr.State(value="zh")
+        template_cleared = gr.State(value=False)
 
         # ---- Event wiring ----
 
+        _TEMPLATE_LINES = {
+            "# Write your solution here using Legesher",
+            "# Use native-language variable and function names",
+        }
+
+        def on_code_change(code: str, cleared: bool):
+            """Strip template comment lines on the user's very first edit, then never again."""
+            if cleared:
+                return gr.update(), True
+            lines = code.split("\n")
+            filtered = [l for l in lines if l.strip() not in _TEMPLATE_LINES]
+            # Remove leading blank lines left behind
+            while filtered and not filtered[0].strip():
+                filtered.pop(0)
+            cleaned = "\n".join(filtered)
+            return cleaned, True
+
+        code_editor.change(
+            fn=on_code_change,
+            inputs=[code_editor, template_cleared],
+            outputs=[code_editor, template_cleared],
+        )
+
         def tier_to_idx(tier_label: str) -> int:
             return TIER_LABELS.index(tier_label)
 
@@ -480,8 +504,8 @@ def build_app() -> gr.Blocks:
         )
 
         clear_btn.click(
-            fn=lambda: ("", "", ""),
-            outputs=[code_editor, stdin_input, run_output],
+            fn=lambda: ("# Write your solution here using Legesher\n# Use native-language variable and function names\n", "", "", False),
+            outputs=[code_editor, stdin_input, run_output, template_cleared],
         )
 
         submit_btn.click(