diff --git a/Source/GUI/GUICommon.cpp b/Source/GUI/GUICommon.cpp
index a0fcf89..7376393 100644
--- a/Source/GUI/GUICommon.cpp
+++ b/Source/GUI/GUICommon.cpp
@@ -2,7 +2,9 @@
 
 #include <QApplication>
 #include <QCoreApplication>
+#include <QFontMetrics>
 #include <QStringList>
+#include <QToolTip>
 
 namespace GUICommon
 {
@@ -71,15 +73,188 @@ QString getNameFromBase(const Common::MemBase base)
   }
 }
 
-void changeApplicationStyle(int index)
+void changeApplicationStyle(const ApplicationStyle style)
 {
-  if (index == 0)
+  QApplication::setStyle(QStringLiteral("fusion"));
+
+  if (style == ApplicationStyle::System)
+  {
+    qApp->setPalette({});
+    QToolTip::setPalette({});
+    qApp->setStyleSheet({});
+    return;
+  }
+
+  if (style == ApplicationStyle::Light)
+  {
+    QPalette palette;
+    palette.setColor(QPalette::All, QPalette::Window, QColor(239, 239, 239));
+    palette.setColor(QPalette::Disabled, QPalette::Window, QColor(239, 239, 239));
+    palette.setColor(QPalette::All, QPalette::WindowText, QColor(0, 0, 0));
+    palette.setColor(QPalette::Disabled, QPalette::WindowText, QColor(190, 190, 190));
+    palette.setColor(QPalette::All, QPalette::Base, QColor(255, 255, 255));
+    palette.setColor(QPalette::Disabled, QPalette::Base, QColor(239, 239, 239));
+    palette.setColor(QPalette::All, QPalette::AlternateBase, QColor(247, 247, 247));
+    palette.setColor(QPalette::Disabled, QPalette::AlternateBase, QColor(247, 247, 247));
+    palette.setColor(QPalette::All, QPalette::ToolTipBase, QColor(255, 255, 220));
+    palette.setColor(QPalette::Disabled, QPalette::ToolTipBase, QColor(255, 255, 220));
+    palette.setColor(QPalette::All, QPalette::ToolTipText, QColor(0, 0, 0));
+    palette.setColor(QPalette::Disabled, QPalette::ToolTipText, QColor(0, 0, 0));
+    palette.setColor(QPalette::All, QPalette::PlaceholderText, QColor(119, 119, 119));
+    palette.setColor(QPalette::Disabled, QPalette::PlaceholderText, QColor(119, 119, 119));
+    palette.setColor(QPalette::All, QPalette::Text, QColor(0, 0, 0));
+    palette.setColor(QPalette::Disabled, QPalette::Text, QColor(190, 190, 190));
+    palette.setColor(QPalette::All, QPalette::Button, QColor(239, 239, 239));
+    palette.setColor(QPalette::Disabled, QPalette::Button, QColor(239, 239, 239));
+    palette.setColor(QPalette::All, QPalette::ButtonText, QColor(0, 0, 0));
+    palette.setColor(QPalette::Disabled, QPalette::ButtonText, QColor(190, 190, 190));
+    palette.setColor(QPalette::All, QPalette::BrightText, QColor(255, 255, 255));
+    palette.setColor(QPalette::Disabled, QPalette::BrightText, QColor(255, 255, 255));
+    palette.setColor(QPalette::All, QPalette::Light, QColor(255, 255, 255));
+    palette.setColor(QPalette::Disabled, QPalette::Light, QColor(255, 255, 255));
+    palette.setColor(QPalette::All, QPalette::Midlight, QColor(202, 202, 202));
+    palette.setColor(QPalette::Disabled, QPalette::Midlight, QColor(202, 202, 202));
+    palette.setColor(QPalette::All, QPalette::Dark, QColor(159, 159, 159));
+    palette.setColor(QPalette::Disabled, QPalette::Dark, QColor(190, 190, 190));
+    palette.setColor(QPalette::All, QPalette::Mid, QColor(184, 184, 184));
+    palette.setColor(QPalette::Disabled, QPalette::Mid, QColor(184, 184, 184));
+    palette.setColor(QPalette::All, QPalette::Shadow, QColor(118, 118, 118));
+    palette.setColor(QPalette::Disabled, QPalette::Shadow, QColor(177, 177, 177));
+    palette.setColor(QPalette::All, QPalette::Highlight, QColor(48, 140, 198));
+    palette.setColor(QPalette::Disabled, QPalette::Highlight, QColor(145, 145, 145));
+    palette.setColor(QPalette::All, QPalette::HighlightedText, QColor(255, 255, 255));
+    palette.setColor(QPalette::Disabled, QPalette::HighlightedText, QColor(255, 255, 255));
+    palette.setColor(QPalette::All, QPalette::Link, QColor(0, 0, 255));
+    palette.setColor(QPalette::Disabled, QPalette::Link, QColor(0, 0, 255));
+    palette.setColor(QPalette::All, QPalette::LinkVisited, QColor(255, 0, 255));
+    palette.setColor(QPalette::Disabled, QPalette::LinkVisited, QColor(255, 0, 255));
+
+    qApp->setPalette(palette);
+    QToolTip::setPalette(palette);
+
+    const int padding{QFontMetrics(QFont()).height() / 2};
+    qApp->setStyleSheet(QString(R"(
+        QToolTip {
+            padding: %1px;
+            border: 1px solid rgb(239, 239, 239);
+            background: rgb(255, 255, 255);
+        }
+    )")
+                            .arg(padding));
+  }
+  else if (style == ApplicationStyle::DarkGray)
   {
-    QApplication::setStyle(QStringLiteral("fusion"));
+    QPalette palette;
+    palette.setColor(QPalette::All, QPalette::Window, QColor(50, 50, 50));
+    palette.setColor(QPalette::Disabled, QPalette::Window, QColor(55, 55, 55));
+    palette.setColor(QPalette::All, QPalette::WindowText, QColor(200, 200, 200));
+    palette.setColor(QPalette::Disabled, QPalette::WindowText, QColor(108, 108, 108));
+    palette.setColor(QPalette::All, QPalette::Base, QColor(25, 25, 25));
+    palette.setColor(QPalette::Disabled, QPalette::Base, QColor(30, 30, 30));
+    palette.setColor(QPalette::All, QPalette::AlternateBase, QColor(38, 38, 38));
+    palette.setColor(QPalette::Disabled, QPalette::AlternateBase, QColor(42, 42, 42));
+    palette.setColor(QPalette::All, QPalette::ToolTipBase, QColor(45, 45, 45));
+    palette.setColor(QPalette::Disabled, QPalette::ToolTipBase, QColor(45, 45, 45));
+    palette.setColor(QPalette::All, QPalette::ToolTipText, QColor(200, 200, 200));
+    palette.setColor(QPalette::Disabled, QPalette::ToolTipText, QColor(200, 200, 200));
+    palette.setColor(QPalette::All, QPalette::PlaceholderText, QColor(90, 90, 90));
+    palette.setColor(QPalette::Disabled, QPalette::PlaceholderText, QColor(90, 90, 90));
+    palette.setColor(QPalette::All, QPalette::Text, QColor(200, 200, 200));
+    palette.setColor(QPalette::Disabled, QPalette::Text, QColor(108, 108, 108));
+    palette.setColor(QPalette::All, QPalette::Button, QColor(54, 54, 54));
+    palette.setColor(QPalette::Disabled, QPalette::Button, QColor(54, 54, 54));
+    palette.setColor(QPalette::All, QPalette::ButtonText, QColor(200, 200, 200));
+    palette.setColor(QPalette::Disabled, QPalette::ButtonText, QColor(108, 108, 108));
+    palette.setColor(QPalette::All, QPalette::BrightText, QColor(75, 75, 75));
+    palette.setColor(QPalette::Disabled, QPalette::BrightText, QColor(255, 255, 255));
+    palette.setColor(QPalette::All, QPalette::Light, QColor(26, 26, 26));
+    palette.setColor(QPalette::Disabled, QPalette::Light, QColor(26, 26, 26));
+    palette.setColor(QPalette::All, QPalette::Midlight, QColor(40, 40, 40));
+    palette.setColor(QPalette::Disabled, QPalette::Midlight, QColor(40, 40, 40));
+    palette.setColor(QPalette::All, QPalette::Dark, QColor(108, 108, 108));
+    palette.setColor(QPalette::Disabled, QPalette::Dark, QColor(108, 108, 108));
+    palette.setColor(QPalette::All, QPalette::Mid, QColor(71, 71, 71));
+    palette.setColor(QPalette::Disabled, QPalette::Mid, QColor(71, 71, 71));
+    palette.setColor(QPalette::All, QPalette::Shadow, QColor(25, 25, 25));
+    palette.setColor(QPalette::Disabled, QPalette::Shadow, QColor(37, 37, 37));
+    palette.setColor(QPalette::All, QPalette::Highlight, QColor(45, 140, 225));
+    palette.setColor(QPalette::Disabled, QPalette::Highlight, QColor(45, 140, 225).darker());
+    palette.setColor(QPalette::All, QPalette::HighlightedText, QColor(255, 255, 255));
+    palette.setColor(QPalette::Disabled, QPalette::HighlightedText, QColor(40, 40, 40));
+    palette.setColor(QPalette::All, QPalette::Link, QColor(40, 130, 220));
+    palette.setColor(QPalette::Disabled, QPalette::Link, QColor(40, 130, 220).darker());
+    palette.setColor(QPalette::All, QPalette::LinkVisited, QColor(110, 70, 150));
+    palette.setColor(QPalette::Disabled, QPalette::LinkVisited, QColor(110, 70, 150).darker());
+
+    qApp->setPalette(palette);
+    QToolTip::setPalette(palette);
+
+    const int padding{QFontMetrics(QFont()).height() / 2};
+    qApp->setStyleSheet(QString(R"(
+        QToolTip {
+            padding: %1px;
+            border: 1px solid rgb(30, 30, 30);
+            background: rgb(45, 45, 45);
+        }
+    )")
+                            .arg(padding));
   }
-  else if (index == 1)
+  else if (style == ApplicationStyle::Dark)
   {
-    QApplication::setStyle(QStringLiteral("windowsvista"));
+    QPalette palette;
+    palette.setColor(QPalette::All, QPalette::Window, QColor(22, 22, 22));
+    palette.setColor(QPalette::Disabled, QPalette::Window, QColor(30, 30, 30));
+    palette.setColor(QPalette::All, QPalette::WindowText, QColor(180, 180, 180));
+    palette.setColor(QPalette::Disabled, QPalette::WindowText, QColor(90, 90, 90));
+    palette.setColor(QPalette::All, QPalette::Base, QColor(35, 35, 35));
+    palette.setColor(QPalette::Disabled, QPalette::Base, QColor(30, 30, 30));
+    palette.setColor(QPalette::All, QPalette::AlternateBase, QColor(40, 40, 40));
+    palette.setColor(QPalette::Disabled, QPalette::AlternateBase, QColor(35, 35, 35));
+    palette.setColor(QPalette::All, QPalette::ToolTipBase, QColor(0, 0, 0));
+    palette.setColor(QPalette::Disabled, QPalette::ToolTipBase, QColor(0, 0, 0));
+    palette.setColor(QPalette::All, QPalette::ToolTipText, QColor(170, 170, 170));
+    palette.setColor(QPalette::Disabled, QPalette::ToolTipText, QColor(170, 170, 170));
+    palette.setColor(QPalette::All, QPalette::PlaceholderText, QColor(100, 100, 100));
+    palette.setColor(QPalette::Disabled, QPalette::PlaceholderText, QColor(100, 100, 100));
+    palette.setColor(QPalette::All, QPalette::Text, QColor(200, 200, 200));
+    palette.setColor(QPalette::Disabled, QPalette::Text, QColor(90, 90, 90));
+    palette.setColor(QPalette::All, QPalette::Button, QColor(30, 30, 30));
+    palette.setColor(QPalette::Disabled, QPalette::Button, QColor(20, 20, 20));
+    palette.setColor(QPalette::All, QPalette::ButtonText, QColor(180, 180, 180));
+    palette.setColor(QPalette::Disabled, QPalette::ButtonText, QColor(90, 90, 90));
+    palette.setColor(QPalette::All, QPalette::BrightText, QColor(75, 75, 75));
+    palette.setColor(QPalette::Disabled, QPalette::BrightText, QColor(255, 255, 255));
+    palette.setColor(QPalette::All, QPalette::Light, QColor(0, 0, 0));
+    palette.setColor(QPalette::Disabled, QPalette::Light, QColor(0, 0, 0));
+    palette.setColor(QPalette::All, QPalette::Midlight, QColor(40, 40, 40));
+    palette.setColor(QPalette::Disabled, QPalette::Midlight, QColor(40, 40, 40));
+    palette.setColor(QPalette::All, QPalette::Dark, QColor(90, 90, 90));
+    palette.setColor(QPalette::Disabled, QPalette::Dark, QColor(90, 90, 90));
+    palette.setColor(QPalette::All, QPalette::Mid, QColor(60, 60, 60));
+    palette.setColor(QPalette::Disabled, QPalette::Mid, QColor(60, 60, 60));
+    palette.setColor(QPalette::All, QPalette::Shadow, QColor(10, 10, 10));
+    palette.setColor(QPalette::Disabled, QPalette::Shadow, QColor(20, 20, 20));
+    palette.setColor(QPalette::All, QPalette::Highlight, QColor(35, 130, 200));
+    palette.setColor(QPalette::Disabled, QPalette::Highlight, QColor(35, 130, 200).darker());
+    palette.setColor(QPalette::All, QPalette::HighlightedText, QColor(240, 240, 240));
+    palette.setColor(QPalette::Disabled, QPalette::HighlightedText, QColor(35, 35, 35));
+    palette.setColor(QPalette::All, QPalette::Link, QColor(40, 130, 220));
+    palette.setColor(QPalette::Disabled, QPalette::Link, QColor(40, 130, 220).darker());
+    palette.setColor(QPalette::All, QPalette::LinkVisited, QColor(110, 70, 150));
+    palette.setColor(QPalette::Disabled, QPalette::LinkVisited, QColor(110, 70, 150).darker());
+
+    qApp->setPalette(palette);
+    QToolTip::setPalette(palette);
+
+    const int padding{QFontMetrics(QFont()).height() / 2};
+    qApp->setStyleSheet(QString(R"(
+        QToolTip {
+            padding: %1px;
+            border: 1px solid rgb(50, 50, 50);
+            background: rgb(10, 10, 10);
+        }
+    )")
+                            .arg(padding));
   }
 }
 
diff --git a/Source/GUI/GUICommon.h b/Source/GUI/GUICommon.h
index 714f41a..aab104c 100644
--- a/Source/GUI/GUICommon.h
+++ b/Source/GUI/GUICommon.h
@@ -14,7 +14,15 @@ extern QStringList g_memBaseNames;
 QString getStringFromType(Common::MemType type, size_t length = 0);
 QString getNameFromBase(Common::MemBase base);
 
-void changeApplicationStyle(int);
+enum class ApplicationStyle
+{
+  System = 0,
+  Light,
+  DarkGray,
+  Dark,
+};
+
+void changeApplicationStyle(ApplicationStyle style);
 
 extern bool g_valueEditing;
 }  // namespace GUICommon
diff --git a/Source/GUI/MainWindow.cpp b/Source/GUI/MainWindow.cpp
index 547e697..15f5877 100644
--- a/Source/GUI/MainWindow.cpp
+++ b/Source/GUI/MainWindow.cpp
@@ -36,9 +36,9 @@ MainWindow::MainWindow()
     restoreGeometry(SConfig::getInstance().getMainWindowGeometry());
   if (SConfig::getInstance().getMainWindowState().size())
     restoreState(SConfig::getInstance().getMainWindowState());
-#ifdef _WIN32
-  GUICommon::changeApplicationStyle(SConfig::getInstance().getTheme());
-#endif
+
+  GUICommon::changeApplicationStyle(
+      static_cast<GUICommon::ApplicationStyle>(SConfig::getInstance().getTheme()));
 
   m_watcher->restoreWatchModel(SConfig::getInstance().getWatchModel());
   m_actAutoHook->setChecked(SConfig::getInstance().getAutoHook());
diff --git a/Source/GUI/Settings/DlgSettings.cpp b/Source/GUI/Settings/DlgSettings.cpp
index f9a58fb..cf5d98a 100644
--- a/Source/GUI/Settings/DlgSettings.cpp
+++ b/Source/GUI/Settings/DlgSettings.cpp
@@ -14,10 +14,13 @@ DlgSettings::DlgSettings(QWidget* parent) : QDialog(parent)
 {
   QGroupBox* grbCoreSettings = new QGroupBox("Core settings");
   m_cmbTheme = new QComboBox();
-  m_cmbTheme->addItem("Dark", 0);
-  m_cmbTheme->addItem("Light", 1);
-  connect(m_cmbTheme, QOverload<int>::of(&QComboBox::currentIndexChanged), this,
-          GUICommon::changeApplicationStyle);
+  m_cmbTheme->addItem("System", static_cast<int>(GUICommon::ApplicationStyle::System));
+  m_cmbTheme->addItem("Light", static_cast<int>(GUICommon::ApplicationStyle::Light));
+  m_cmbTheme->addItem("Dark Gray", static_cast<int>(GUICommon::ApplicationStyle::DarkGray));
+  m_cmbTheme->addItem("Dark", static_cast<int>(GUICommon::ApplicationStyle::Dark));
+  connect(m_cmbTheme, &QComboBox::currentIndexChanged, this, [](const int index) {
+    GUICommon::changeApplicationStyle(static_cast<GUICommon::ApplicationStyle>(index));
+  });
 
   QFormLayout* coreSettingsInputLayout = new QFormLayout();
   coreSettingsInputLayout->addRow("Theme", m_cmbTheme);
@@ -126,9 +129,7 @@ DlgSettings::DlgSettings(QWidget* parent) : QDialog(parent)
   grbMemorySizeSettings->setLayout(memorySettingsInputLayout);
 
   QVBoxLayout* mainLayout = new QVBoxLayout;
-#ifdef _WIN32
   mainLayout->addWidget(grbCoreSettings);
-#endif
   mainLayout->addWidget(grbTimerSettings);
   mainLayout->addWidget(grbScannerSettings);
   mainLayout->addWidget(grbViewerSettings);