message: Fix the scrollbar thumb colour after the recent sass upgrade.
diff: BODY {
  --scrollbar-background-color: transparent;
  --scrollbar-track-background-color: transparent;
  - --scrollbar-thumb-background-color: lighten($base-background-color, 30%);
  - --scrollbar-thumb-hover-background-color: lighten($base-background-color, 40%);
  + --scrollbar-thumb-background-color: #{lighten($base-background-color, 30%)};
  + --scrollbar-thumb-hover-background-color: #{lighten($base-background-color, 40%)};
  }
  