In DNN, a Theme is everything that determines the whole look and feel of a page. This includes things like
- Colors and logos
- Arrangement of panes (the placeholders for content on the page)
- Placement of header / footer
- Navigation
- Footer contents
Since the theme "wraps" everything in the page, it will also be responsible for hidden page-wide functionality like
- page title
- metadata
- loading global javascript or css files