Update CSS styles in app.py to enhance layout and box-sizing

Removed redundant font size declaration and added specific box-sizing property to improve the layout of the application. This change aims to enhance the visual presentation and user experience.

app.py

@@ -59,12 +59,11 @@ st.markdown("""
     div[data-baseweb="select"] > div {
         background-color: #DAA520;
         color: white;
-    )
-
-    div {
-        font-size: 18px;
     }
 
+    .stVerticalBlock.st-emotion-cache-6kio1c.eu6p4el3 {
+        box-sizing: content-box !important;
+    }
 
 </style>""", unsafe_allow_html=True)