Update app.py

app.py

@@ -746,9 +746,9 @@ centered_col_css = """
     border-color: purple !important;
 }
 #answer-reference-btn {
-    background-color: #E6E6FA !important;
+    background-color: #6B6BFF !important;
     color: white !important;
-    border-color: #E6E6FA !important;
+    border-color: #6B6BFF !important;
 }
 #clear_btn {
     background-color: #F08080 !important;