improve:主题切换

Ink Canvas/MainWindow_cs/MW_FloatingBarIcons.cs

@@ -3714,6 +3714,35 @@ namespace Ink_Canvas
                         break;
                 }
 
+                // 根据主题设置高光颜色
+                Color highlightBackgroundColor;
+                Color highlightBarColor;
+                bool isDarkTheme = Settings.Appearance.Theme == 1 || 
+                                   (Settings.Appearance.Theme == 2 && !IsSystemThemeLight());
+                
+                if (isDarkTheme)
+                {
+                    highlightBackgroundColor = Color.FromArgb(21, 102, 204, 255); 
+                    highlightBarColor = Color.FromRgb(102, 204, 255); 
+                }
+                else
+                {
+                    highlightBackgroundColor = Color.FromArgb(21, 59, 130, 246); 
+                    highlightBarColor = Color.FromRgb(37, 99, 235); 
+                }
+
+                // 设置高光背景颜色
+                FloatingbarSelectionBG.Background = new SolidColorBrush(highlightBackgroundColor);
+                
+                if (FloatingbarSelectionBG.Child is System.Windows.Controls.Canvas canvas && canvas.Children.Count > 0)
+                {
+                    var firstChild = canvas.Children[0];
+                    if (firstChild is Border innerBorder)
+                    {
+                        innerBorder.Background = new SolidColorBrush(highlightBarColor);
+                    }
+                }
+
                 // 设置高光位置
                 FloatingbarSelectionBG.Visibility = Visibility.Visible;
                 System.Windows.Controls.Canvas.SetLeft(FloatingbarSelectionBG, position);