Like Redmine one the look and feel of the WikiNG elements (e.g. blocks, smileys, markers etc) can be customized with a custom CSS theme. But the name of the theme should be identical to the system theme name.
To create a new theme you should create a CSS file in the
assets/stylesheets directory. For example, if the system theme has name
red-andy (this name can be found in the Redmine
public/themes directory) the filename of the WikiNG theme should be
For sample theme check source:assets/stylesheets/red-andy.css.
The CSS file of the theme is enabled automatically when you enable the system theme with the same name.