Refactor ExampleApp theme and background color; enhance slider with divisions and labels

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

example/lib/main.dart

@@ -16,10 +16,6 @@ class ExampleApp extends StatelessWidget {
   Widget build(BuildContext context) {
     return MaterialApp(
       debugShowCheckedModeBanner: false,
-      theme: ThemeData(
-        useMaterial3: true,
-        colorScheme: ColorScheme.fromSeed(seedColor: const Color(0xFF24A6A8)),
-      ),
       home: const ExampleHome(),
     );
   }
@@ -83,7 +79,6 @@ class _ExampleHomeState extends State<ExampleHome> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      backgroundColor: const Color(0xFF0D121A),
       appBar: AppBar(
         title: const Text('holo_shiny example'),
       ),
@@ -253,6 +248,8 @@ class _LabeledSlider extends StatelessWidget {
         Text('$label: ${value.toStringAsFixed(2)}'),
         Slider(
           value: value,
+          divisions: 20,
+          label: value.toStringAsFixed(2),
           onChanged: onChanged,
         ),
       ],

test/shiny_widget_test.dart

@@ -26,6 +26,14 @@ void main() {
     expect(shinyCard.sparkleShape.primary, 0.0);
   });
 
+  test('default opacity is 1.0', () {
+    const Shiny shiny = Shiny(child: SizedBox.shrink());
+    const ShinyCard shinyCard = ShinyCard();
+
+    expect(shiny.opacity, 1.0);
+    expect(shinyCard.opacity, 1.0);
+  });
+
   test('custom sparkle factories produce expected specs', () {
     final SparkleShapeSpec star =
         SparkleShapeSpec.customStar(points: 7, innerRatio: 0.33);