fix/themes

Signed-off-by: Collecting <collecting@noreply.localhost>

src/citron/uisettings.cpp

@@ -2,6 +2,8 @@
 // SPDX-FileCopyrightText: 2025 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include <QApplication>
+#include <QPalette>
 #include <QSettings>
 #include "common/fs/fs.h"
 #include "common/fs/path_util.h"
@@ -33,13 +35,29 @@ namespace UISettings {
     }};
 
     bool IsDarkTheme() {
-        const auto& theme = UISettings::values.theme;
+        const auto& theme_name = UISettings::values.theme;
-        return theme == std::string("qdarkstyle") || theme == std::string("qdarkstyle_midnight_blue") ||
+
-        theme == std::string("colorful_dark") || theme == std::string("colorful_midnight_blue");
+        // Priority 1: Check for explicitly chosen dark themes.
+        if (theme_name == "qdarkstyle" || theme_name == "colorful_dark" ||
+            theme_name == "qdarkstyle_midnight_blue" || theme_name == "colorful_midnight_blue") {
+            return true;
+        }
+
+        // Priority 2: Check for adaptive themes ("default" and "colorful").
+        if (theme_name == "default" || theme_name == "colorful") {
+            const QPalette palette = qApp->palette();
+            const QColor text_color = palette.color(QPalette::WindowText);
+            const QColor base_color = palette.color(QPalette::Window);
+            return text_color.value() > base_color.value();
+        }
+
+        // Fallback for any other unknown themes is to assume they are light.
+        return false;
     }
 
     Values values = {};
 
+    // definition for the function.
     u32 CalculateWidth(u32 height, Settings::AspectRatio ratio) {
         switch (ratio) {
         case Settings::AspectRatio::R4_3: