improve toner indicator

lib/pages/printer_details/toner_indicator.dart

@@ -17,7 +17,11 @@ class TonerIndicator extends StatelessWidget {
     return Container(
       width: width,
       height: height,
-      color: grey,
+      clipBehavior: Clip.antiAlias,
+      decoration: BoxDecoration(
+        color: Colors.black45,
+        borderRadius: BorderRadius.circular(height / 2),
+      ),
       child: Stack(
         alignment: Alignment.center,
         children: [