Ubuntu runs on a range of devices, varying from a small phone to a 50-inch television, from low to high resolutions and from 100 to 400+ pixel densities.
We have a framework that helps you to retain a uniform experience across these screen sizes.
In brief, a new measurement unit is defined called the grid unit. The ratio of pixels per grid unit depends on the pixel density and viewing distance. By defining sizes in grid units, our UI elements automatically scale between devices – and retain a similar perceived size.
Note: Grid units will help when communicating between designers and developers too; by saving a design with the grid overlaid, the size and positioning of each element in grid units is clear.