fix: improve radio checked dot visibility

app.py

@@ -361,6 +361,19 @@ ul.options, .gr-dropdown-options {
     color: var(--text) !important;
 }
 
+/* Radio dot visibility (checked) */
+.gr-check-radio input[type="radio"] {
+    width: 16px !important;
+    height: 16px !important;
+    accent-color: #111827 !important; /* black dot */
+}
+
+fieldset label.selected input[type="radio"] {
+    accent-color: #111827 !important;
+    background-color: #ffffff !important;
+    border: 1px solid #111827 !important;
+}
+
 /* Footer */
 .footer-text, .footer-text p {
     color: var(--muted) !important;