feat: stretch chat window to window height

app.py

@@ -323,7 +323,13 @@ def chat(message, history):
         yield f"{text}\n\n{ERROR_MESSAGE}" if text else ERROR_MESSAGE
 
 
-with gr.Blocks(css_paths=["static/deval.css"],theme = gr.themes.Default(primary_hue="blue", secondary_hue="yellow"),) as demo:
+with gr.Blocks(
+    css_paths=["static/deval.css"],
+    theme=gr.themes.Default(primary_hue="blue", secondary_hue="yellow"),
+    # grow top-level children with scale >= 1 to the window height; the header row
+    # and the input group have no scale, so only the transcript stretches
+    fill_height=True,
+) as demo:
     # ── Logo + Header + Logout ────────────────────────────────
 
 
@@ -362,8 +368,16 @@ with gr.Blocks(css_paths=["static/deval.css"],theme = gr.themes.Default(primary_
         type="messages",
         multimodal=MULTIMODAL,
         textbox=upload_textbox,
-        # ChatInterface would otherwise label the transcript "Chatbot"
-        chatbot=gr.Chatbot(type="messages", show_label=False),
+        # ChatInterface would otherwise label the transcript "Chatbot". scale=1 is
+        # what makes fill_height stretch it: 400px is the floor it grows from, so
+        # the transcript takes the window height left over by header and input.
+        chatbot=gr.Chatbot(
+            type="messages",
+            show_label=False,
+            scale=1,
+            height=400,
+            elem_id="chat-window",
+        ),
         editable=True,
         concurrency_limit=20,
         save_history=True,