A system for presenting a common user interface (UI) of multiple applications on diverse client computing devices as a web page that includes a set of UI elements leading to the multiple applications. The diverse client computing devices have display screens of diverse sizes. In the system, backend servers host a UI infrastructure including the common UI and one or more object page floorplans of respective UI object pages representing the multiple applications and representing application information and data on the diverse client computing devices. Design tools are available to process the object page floorplans to display, create, or edit the UI object pages. The object page floorplans include a first object page layout including a title bar, a header, an expanded default state, a navigation control, a content area, and a footer toolbar containing actions that are performed upon a corresponding first UI object page.