Update CSS selector in app.py to simplify box-sizing implementation

Changed the CSS selector for box-sizing to a more general format, aiming to streamline the styling process and maintain layout consistency across elements. This adjustment contributes to a cleaner and more efficient codebase.

app.py

@@ -61,7 +61,7 @@ st.markdown("""
         color: white;
     }
 
-    div[style*="box-sizing"] {
+    div{
         box-sizing: content-box !important;
     }