Index: src/kmessagewidget.cpp
===================================================================
--- src/kmessagewidget.cpp
+++ src/kmessagewidget.cpp
@@ -32,6 +32,9 @@
 #include <QToolButton>
 #include <QStyle>
 
+#include <QStandardPaths>
+#include <QSettings>
+
 //---------------------------------------------------------------------
 // KMessageWidgetPrivate
 //---------------------------------------------------------------------
@@ -254,32 +257,65 @@
     return d->messageType;
 }
 
+static QColor qColorFromSettings(const QSettings *settings, const QString &key, QColor value = QColor())
+{
+    if (settings && settings->contains(key)) {
+        QStringList rgb = settings->value(key).toStringList();
+        if (rgb.size() == 3) {
+            value.setRgb(rgb.at(0).toInt(), rgb.at(1).toInt(), rgb.at(2).toInt());
+        } else if (rgb.size() >= 3) {
+            value.setRgb(rgb.at(0).toInt(), rgb.at(1).toInt(), rgb.at(2).toInt(), rgb.at(3).toInt());
+        }
+    }
+    return value;
+}
+
 void KMessageWidget::setMessageType(KMessageWidget::MessageType type)
 {
     d->messageType = type;
     QColor bgBaseColor;
-
-    // We have to hardcode colors here because KWidgetsAddons is a tier 1 framework
-    // and therefore can't depend on any other KDE Frameworks
-    // The following RGB color values come from the "default" scheme in kcolorscheme.cpp
+    const QPalette palette = QGuiApplication::palette();
+    qreal bgBaseColorAlpha = 0.2;
+
+    // We cannot use KColorScheme here because KWidgetsAddons is a tier 1 framework
+    // and therefore can't depend on any other KDE Frameworks. We thus try to get
+    // the colours that interest us directly from the global settings store using QSettings.
+    // It that fails we use hardcoded colours, or the highlight colour (for Information).
+    // The hardcoded RGB color values come from the "default" scheme in kcolorscheme.cpp
+    const QString kdeGlobals = QStandardPaths::locate(QStandardPaths::ConfigLocation, QStringLiteral("kdeglobals"));
+    const QString themeGroup = QStringLiteral("Colors:Window");
+    QSettings *settings = !kdeGlobals.isEmpty() ? new QSettings(kdeGlobals, QSettings::IniFormat) : nullptr;
+    if (settings && settings->childGroups().contains(themeGroup)) {
+        settings->beginGroup(themeGroup);
+    } else {
+        delete settings;
+        settings = nullptr;
+    }
     switch (type) {
     case Positive:
-        bgBaseColor.setRgb(39, 174,  96); // Window: ForegroundPositive
+        bgBaseColor = qColorFromSettings(settings, QStringLiteral("ForegroundPositive"), QColor(39, 174, 96));
         break;
-    case Information:
-        bgBaseColor.setRgb(61, 174, 233); // Window: ForegroundActive
+    case Information: {
+        bgBaseColor = qColorFromSettings(settings, QStringLiteral("ForegroundActive"), palette.highlight().color());
+        // the alpha component is based on the perceived brightness (CIE-XYZ 1931) of the background colour
+        qreal bgIntensity = 0.299 * bgBaseColor.redF() + 0.586 * bgBaseColor.greenF() + 0.115 * bgBaseColor.blueF();
+        bgBaseColorAlpha = 0.5 * bgIntensity;
         break;
+    }
     case Warning:
-        bgBaseColor.setRgb(246, 116, 0); // Window: ForegroundNeutral
+        bgBaseColor = qColorFromSettings(settings, QStringLiteral("ForegroundNeutral"), QColor(246, 116, 0));
         break;
     case Error:
-        bgBaseColor.setRgb(218, 68, 83); // Window: ForegroundNegative
+        bgBaseColor = qColorFromSettings(settings, QStringLiteral("ForegroundNegative"), QColor(218, 68, 83));
         break;
     }
-    const qreal bgBaseColorAlpha = 0.2;
+    if (settings) {
+        settings->endGroup();
+        delete settings;
+    }
+
     bgBaseColor.setAlphaF(bgBaseColorAlpha);
 
-    const QPalette palette = QGuiApplication::palette();
     const QColor windowColor = palette.window().color();
     const QColor textColor = palette.text().color();
     const QColor border = bgBaseColor;