Update app.py

app.py

@@ -55,6 +55,8 @@ html, body, .stApp {
     max-width: 768px !important; /* حداکثر عرض صفحه */
     margin: 0 auto; /* وسط‌چین کردن محتوا */
     width: 100% !important
+    background-color: var(--background) !important;
+    color: var(--text) !important;
 }
 
 @media (min-width: 768px) {    
@@ -91,14 +93,14 @@ html, body, .stApp {
     #root, .stApp {
         background: transparent !important;
         padding: 0 !important;
-        margin: 0 !important;
+        margin: 0 auto;
     }
 
     /* Ensure Streamlit's main container doesn't add extra space */
     [data-testid="stAppViewContainer"] > div {
         max-width: 100% !important;
         padding: 0 !important;
-        margin: 0 !important;
+        margin: 0 auto;
     }
 
     /* Webkit scrollbar styles */