Update app.py

app.py

@@ -118,13 +118,13 @@ css = """
 @media (prefers-color-scheme: dark) {
     [data-testid='textbox'] {
         color: white !important;
-        background-color: gray !important;
+        background-color: black !important;
     }
 }
 @media (prefers-color-scheme: light) {
     [data-testid='textbox'] {
         color: white !important;
-        background-color: gray !important;
+        background-color: black !important;
     }
 }
 """