Adapt markup to typographic styles

- Mail Messages List

UI/WebServerResources/scss/_devtools.scss

@@ -21,4 +21,9 @@ html.dev {
     content: " ";
     z-index: 1000;
   }
+}
+// for visibility while devopping
+// ____________________________________________________________________________
+.md-tile-left {
+  background-color: rgba(224, 255, 255, 0.5);
 }