all themes now have contrasting text colors based on slide bg

css/theme/source/night.scss

@@ -28,6 +28,9 @@ $headingLetterSpacing: -0.03em;
 $headingTextTransform: none;
 $selectionBackgroundColor: #e7ad52;
 
+// Change text colors against light slide backgrounds
+@include light-bg-text-color(#222);
+
 
 // Theme template ------------------------------
 @import "../template/theme";