Representations of a set of cards are displayed via an application authoring interface. A given card represents one or more screen layouts of an application, and contents of a particular card are based on contents of a data sheet materialized in accordance with a data model which enables automatic instantiation of child data sheets associated with a parent cell within a parent data sheet. In response to detecting an edit operation directed at a particular card, an updated representation of the particular card is displayed at the first application authoring interface, and a screen layout corresponding to the updated representation is rendered at a particular mobile computing device.