Enlarge default CKEditor font size

qa-plugin/wysiwyg-editor/ckeditor/config.js

@@ -35,4 +35,7 @@ CKEDITOR.editorConfig = function( config ) {
 
 	// Prevent blank paragraphs
 	config.fillEmptyBlocks = false;
+
+	// Add custom CSS
+	config.contentsCss = [CKEDITOR.getUrl('contents.css'), CKEDITOR.getUrl('contents-custom.css')];
 };

qa-plugin/wysiwyg-editor/ckeditor/contents-custom.css

+/**
+ * Q2A custom CSS for CKEditor
+ * Increases default font size. You can add custom styles here to match your theme, but make sure that you do not overwrite it when upgrading Q2A!
+ */
+
+body, .cke_editable {
+	font-size: 15px;
+}