2 files changed, 15 insertions, 2 deletions
diff --git a/src/imports/controls/material/qquickmaterialstyle.cpp b/src/imports/controls/material/qquickmaterialstyle.cpp
index 7e9ba001..76d81e5f 100644
--- a/src/imports/controls/material/qquickmaterialstyle.cpp
+++ b/src/imports/controls/material/qquickmaterialstyle.cpp
@@ -428,6 +428,15 @@ static QColor alphaBlend(const QColor &bg, const QColor &fg)
     return result;
 }
 
+extern bool qt_is_dark_system_theme();
+
+static QQuickMaterialStyle::Theme effectiveTheme(QQuickMaterialStyle::Theme theme)
+{
+    if (theme == QQuickMaterialStyle::System)
+        theme = qt_is_dark_system_theme() ? QQuickMaterialStyle::Dark : QQuickMaterialStyle::Light;
+    return theme;
+}
+
 QQuickMaterialStyle::QQuickMaterialStyle(QObject *parent) : QQuickStyleAttached(parent),
     m_explicitTheme(false),
     m_explicitPrimary(false),
@@ -462,6 +471,9 @@ QQuickMaterialStyle::Theme QQuickMaterialStyle::theme() const
 
 void QQuickMaterialStyle::setTheme(Theme theme)
 {
+    if (theme == System)
+        theme = qt_is_dark_system_theme() ? Dark : Light;
+
     m_explicitTheme = true;
     if (m_theme == theme)
         return;
@@ -1208,7 +1220,7 @@ void QQuickMaterialStyle::init()
         QByteArray themeValue = resolveSetting("QT_QUICK_CONTROLS_MATERIAL_THEME", settings, QStringLiteral("Theme"));
         Theme themeEnum = toEnumValue<Theme>(themeValue, &ok);
         if (ok)
-            defaultTheme = m_theme = themeEnum;
+            defaultTheme = m_theme = effectiveTheme(themeEnum);
         else if (!themeValue.isEmpty())
             qWarning().nospace().noquote() << "Material: unknown theme value: " << themeValue;
 
diff --git a/src/imports/controls/material/qquickmaterialstyle_p.h b/src/imports/controls/material/qquickmaterialstyle_p.h
index 7572d38c..59858a5e 100644
--- a/src/imports/controls/material/qquickmaterialstyle_p.h
+++ b/src/imports/controls/material/qquickmaterialstyle_p.h
@@ -109,7 +109,8 @@ class QQuickMaterialStyle : public QQuickStyleAttached
 public:
     enum Theme {
         Light,
-        Dark
+        Dark,
+        System
     };
 
     enum Color {