update

src/sass/gtk/_common-4.0.scss

@@ -1639,6 +1639,13 @@ headerbar {
     }
   }
 
+  button.star {
+    min-height: 24px;
+    min-width: 24px;
+    padding: ($medium-size - 24px) / 2;
+    @extend %circular-button;
+  }
+
   entry { @extend %titlebar-entry; }
 
   .linked:not(.vertical) > entry:not(:only-child) { border-radius: $corner-radius; }

src/sass/gtk/apps/_gnome-4.0.scss

@@ -670,6 +670,7 @@ screenshot-carousel button,
     font-size: 105%;
     font-weight: normal;
     box-shadow: none;
+    background-color: $fill;
   }
 
   // Styling for specific category buttons.