A system and methods for facilitating adaptive grid-based document layout. More particularly, the present invention features a new approach to adaptive grid-based document layout that utilizes a set of adaptive templates that are configurable in a range of different pages sizes and viewing conditions. The templates include various element types and constraint-based relationships that define the layout of elements with reference to viewing conditions under which the document content will be displayed and that define other content properties. Through a layout engine and paginator, the present invention determines a desirable sequence of templates to use for adapting document content. Additionally, the present invention provides a template authoring tool and user interface for interactively drawing and arranging layout elements within an adaptive template.