Refine piano key pressed highlight rendering

CHANGELOG.md

@@ -19,6 +19,9 @@ The format is based on [Keep a Changelog][1], and this project adheres to
 
 - Refined piano key rendering with a top-edge shadow gradient for stronger
   depth/anchoring and improved contrast for top marker caps.
+- Updated pressed piano key highlights to use a unified accent color with
+  layered shading/gradient treatment for better contrast across white and black
+  keys.
 
 ### Fixed
 

lib/features/piano/models/piano_palette.dart

@@ -4,17 +4,15 @@ import 'package:flutter/material.dart';
 class PianoPalette {
   final Color background;
   final Color whiteKey;
-  final Color whiteKeyHighlight;
+  final Color pressedKeyHighlight;
   final Color blackKey;
-  final Color blackKeyHighlight;
   final Color border;
 
   const PianoPalette({
     required this.background,
     required this.whiteKey,
-    required this.whiteKeyHighlight,
+    required this.pressedKeyHighlight,
     required this.blackKey,
-    required this.blackKeyHighlight,
     required this.border,
   });
 }
@@ -24,28 +22,13 @@ PianoPalette buildPianoPalette(ColorScheme cs) {
 
   final background = cs.surfaceContainerLow;
 
-  Color overlayOn(Color base, Color overlay, double opacity) =>
-      Color.alphaBlend(overlay.withValues(alpha: opacity), base);
-
   final whiteKey = isDark
       ? Color.alphaBlend(cs.surface.withValues(alpha: 0.18), Colors.white)
       : Colors.white;
 
-  final primaryTooClose =
-      (whiteKey.computeLuminance() - cs.primary.computeLuminance()).abs() <
-      0.10;
-
-  final pressedOverlay = (isDark && primaryTooClose)
-      ? cs.primaryContainer
-      : cs.primary;
-
-  final whiteKeyHighlight = isDark
-      ? overlayOn(whiteKey, pressedOverlay, 0.18)
-      : cs.primaryContainer;
-
   final blackKey = const Color(0xFF111111);
 
-  final blackKeyHighlight = isDark
+  final pressedKeyHighlight = isDark
       ? Color.alphaBlend(whiteKey.withValues(alpha: 0.18), cs.primaryContainer)
       : Color.alphaBlend(whiteKey.withValues(alpha: 0.18), cs.primary);
 
@@ -57,9 +40,8 @@ PianoPalette buildPianoPalette(ColorScheme cs) {
   return PianoPalette(
     background: background,
     whiteKey: whiteKey,
-    whiteKeyHighlight: whiteKeyHighlight,
+    pressedKeyHighlight: pressedKeyHighlight,
     blackKey: blackKey,
-    blackKeyHighlight: blackKeyHighlight,
     border: border,
   );
 }

lib/features/piano/widgets/piano_keyboard/piano_keyboard.dart

@@ -55,10 +55,9 @@ class PianoKeyboard extends StatelessWidget {
           highlightedNoteNumbers: highlightedNoteNumbers,
 
           whiteKeyColor: palette.whiteKey,
-          whiteKeyHighlightColor: palette.whiteKeyHighlight,
+          pressedKeyHighlightColor: palette.pressedKeyHighlight,
           whiteKeyBorderColor: palette.border,
           blackKeyColor: palette.blackKey,
-          blackKeyHighlightColor: palette.blackKeyHighlight,
           backgroundColor: palette.background,
 
           decorations: decorations,