Update app.py

app.py

@@ -253,7 +253,31 @@ with block:
             baseline_datatype = ['markdown'] + ['number'] * len(metric_names)            
 
             styler = build_leaderboard_styler()
-        
+
+            gr.Markdown(
+                """
+            ### Method-name colour legend  
+            <span style='color:green; font-weight:bold;'>Green</span>  Classical (hand-crafted) representations  
+            <span style='color:blue;  font-weight:bold;'>Blue</span>  Small-scale learned representations  
+            <span style='color:red;   font-weight:bold;'>Red</span>  Large-scale learned representations  
+            <span style='color:orange;font-weight:bold;'>Orange</span>  Multimodal / composite representations
+            """,
+                elem_classes="leaderboard-note",
+            )
+            
+            gr.Markdown(
+                """
+            ### Metric-cell shading  
+            <span style='background-color:#006400; color:white; padding:0 .4rem; border-radius:.2rem;'>1</span>
+            <span style='background-color:#228B22; color:white; padding:0 .4rem; border-radius:.2rem;'>2</span>
+            <span style='background-color:#32CD32; color:black; padding:0 .4rem; border-radius:.2rem;'>3</span>
+            <span style='background-color:#7CFC00; color:black; padding:0 .4rem; border-radius:.2rem;'>4</span>
+            <span style='background-color:#ADFF2F; color:black; padding:0 .4rem; border-radius:.2rem;'>5</span>
+             = top-five scores (darkest → best)
+            """,
+                elem_classes="leaderboard-note",
+            )
+
             with gr.Row(show_progress=True, variant='panel'):
                 data_component = gr.Dataframe(
                     value=styler,