The tp-banner is a class used for Piano's Offer templates and serves as a default container for displaying Offer templates in certain scenarios.
This tp-banner class is automatically added to the container when an Offer template contains the "banner" directive and when displaying templates through the "Show Offer" action card in Composer.
When an inline template is shown using the "Show Offer" action card, the tp-banner class is added to the corresponding container. This enables the banner to become sticky, following the user as they scroll on the page.
The tp-banner class is not automatically added to the container when using the "Show Template" action card. To achieve a sticky banner when using "Show Template", an alternative solution would be to use custom CSS and JavaScript to make the inline banner sticky.