1. A computer-implemented method comprising: receiving, via a user interface, a user request to render, in a web browser executing on a first type of media device, a structured document in a layout specific to a second type of media device having a different display requirement than the first type of media device, the second type of media device being selected from a plurality of predefined types of media devices; and determining a visual layout of a browser presentation of the structured document in accordance with a style property encoded in a set of presentation semantics associated with the second type of media device.