feat: 添加标题按钮的悬停背景色设置以支持深浅色模式

MainForm.cs

@@ -270,6 +270,22 @@ namespace TimerApp
             btnClose.ForeColor = text;
             btnMin.ForeColor = text;
 
+            // Set hover background colors for title buttons
+            if (dark)
+            {
+                // 深色模式下使用深色悬停背景
+                btnClose.FlatAppearance.MouseOverBackColor = Color.FromArgb(232, 17, 35); // 深色模式下的红色（稍微暗一点）
+                btnMin.FlatAppearance.MouseOverBackColor = Color.FromArgb(63, 63, 70);
+                btnTheme.FlatAppearance.MouseOverBackColor = Color.FromArgb(63, 63, 70);
+            }
+            else
+            {
+                // 浅色模式下使用浅色悬停背景
+                btnClose.FlatAppearance.MouseOverBackColor = Color.Red;
+                btnMin.FlatAppearance.MouseOverBackColor = Color.FromArgb(220, 220, 220); // 浅灰色，接近标题栏背景
+                btnTheme.FlatAppearance.MouseOverBackColor = Color.FromArgb(220, 220, 220); // 浅灰色，接近标题栏背景
+            }
+
             // Theme button with Segoe MDL2 Assets
             btnTheme.ForeColor = text;
             btnTheme.Font = new Font("Segoe MDL2 Assets", 10F, FontStyle.Regular, GraphicsUnit.Point);