1. A computer-implemented method, comprising: accessing, by a processor, data identifying a plurality of interface items to be rendered in a graphical interface; identifying, by the processor, first constraint data based on a first layout of a first size, wherein the first layout includes the plurality of interface items, wherein the first constraint data specifies, for each of the plurality of interface items, a respective first arrangement or size of the interface item; identifying, by the processor, second constraint data based on a second layout of a second size different from the first size, wherein the second layout includes the plurality of interface items, wherein the second constraint data specifies, for each of the plurality of interface items, a respective second arrangement or size of the interface item; determining, by the processor, an output size for outputting the graphical interface; determining, by the processor, an arrangement of the plurality of interface items based on the determined output size for outputting the graphical interface and at least one of the first constraint data specifying first sizes or arrangements of the plurality of interface items in the first layout of the first size and the second constraint data specifying second sizes or arrangements of the plurality of interface items in the second layout of the second size; and providing, by the processor, output to render the graphical interface in the determined output size and including the plurality of interface items, the plurality of interface items positioned according to the arrangement determined using the first constraint data, the second constraint data, and the determined output size.