$public theme set#
This would allow
<% require themedCSS('style.css') %> to find a file committed to public/css/style.css.
$default theme set#
$themeset - Any $ prefixed name will refer to a set of themes. By default only $default set is configured, which represents all module roots with a templates directory.
To define extra themes simply add extra entries to the SilverStripe\View\SSViewer.themes configuration array. You will probably always want to ensure that you include ‘$default’ in your list of themes to ensure that the base templates are used when required.