This page is an example of how cubes can be resized both vertically and horizontally based on a percentage of the window width. These cubes are set at 20 and 25 percent respectively (decimal numbers are also allowed for more exact sizing).

The resizing is done by a small bit of CSS, see source code of this page for details. There is a minimum width defined for first cube which is 80 pixels.

Next 2 cubes are a little larger because the height is increased to adjust for the button bar and slider (see best appearance recommendation in the Using Simulator in Web Pages section in AnimCubeJS documentation).