Refine tab styling border width for subtle visual enhancement

Adjusted the selected tab border width from 5px to 3px, maintaining the golden color scheme while creating a more subtle and refined visual highlight.

app.py

@@ -48,7 +48,7 @@ st.markdown("""
 
     .stTabs [aria-selected="true"] {
         background-color: #DAA520;
-        border: 5px solid #FFD700;
+        border: 3px solid #FFD700;
         color: white;
     }