Styles are applied to templates either as default styles or by explicitly setting the style on a template

Default Styles are set in the Content Template Settings record, and there is a setting for each of email, word, and PDF documents. When one is generated for a template which does not have a specific style et then that default style will be used. This screenshot shows default styles set in a content template settings record

Where a style other than the default style I required for a template, then a style can be set directly on that template. In this case it is used for all generation types for that template. This screenshot shows a specific style selected on a content template record