For situations where the spinner's background is an image or can be more than one color. The halo effect crops the spinner's background to a cicle, providing a consistent display in IE.
For recommended CSS, learn more here.
You may choose from two file formats: GIF or PNG.
GIFs can animate, but cannot fully support continuous transparency. Generated PNGs are sprite, and some javscript and CSS are required to animate them. However, PNGs fully support transparency.
For more information, please see the docs
You may choose one background color and multiple foreground colors.
The spinner will use each foreground color you select from left to right for each line of the spinner. If there are more lines than colors, it will repeat this process until there are no more lines.