Index: src/kmessagewidget.cpp
===================================================================
--- src/kmessagewidget.cpp
+++ src/kmessagewidget.cpp
@@ -258,29 +258,40 @@
 {
     d->messageType = type;
     QColor bgBaseColor;
+    const QPalette palette = QGuiApplication::palette();
+    qreal bgBaseColorAlpha = 0.2;
+    // the message background colour takes the widget background colour
+    // into consideration and thus should use the actual receiving widget
+    // for best results.
+    const QColor windowColor = KMessageWidget::palette().window().color();
 
-    // We have to hardcode colors here because KWidgetsAddons is a tier 1 framework
+    // We have to hardcode some 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
+    // The hardcoded RGB color values come from the "default" scheme in kcolorscheme.cpp
     switch (type) {
     case Positive:
-        bgBaseColor.setRgb(39, 174,  96); // Window: ForegroundPositive
+        bgBaseColor = palette.highlight().color();
+        bgBaseColorAlpha = 0.4;
         break;
-    case Information:
-        bgBaseColor.setRgb(61, 174, 233); // Window: ForegroundActive
+    case Information: {
+        bgBaseColor = palette.toolTipBase().color();
+        // the alpha component is based on the perceived brightness (CIE-XYZ 1931) of the background colour
+        // and its difference with receiving widget's background intensity: half the average of those values,
+        // constrained by the background intensity itself.
+        qreal bgIntensity = 0.299 * bgBaseColor.redF() + 0.586 * bgBaseColor.greenF() + 0.115 * bgBaseColor.blueF();
+        qreal windowIntensity = 0.299 * windowColor.redF() + 0.586 * windowColor.greenF() + 0.115 * windowColor.blueF();
+        bgBaseColorAlpha = 0.5 * qMax((bgIntensity + (1 - windowIntensity)), bgIntensity);
         break;
+    }
     case Warning:
         bgBaseColor.setRgb(246, 116, 0); // Window: ForegroundNeutral
         break;
     case Error:
         bgBaseColor.setRgb(218, 68, 83); // Window: ForegroundNegative
         break;
     }
-    const qreal bgBaseColorAlpha = 0.2;
     bgBaseColor.setAlphaF(bgBaseColorAlpha);
 
-    const QPalette palette = QGuiApplication::palette();
-    const QColor windowColor = palette.window().color();
     const QColor textColor = palette.text().color();
     const QColor border = bgBaseColor;