For many elements in item views, such as edges, nodes, ports, cell background, and ribbon tabs, it is possible to apply a custom color. 

The color values used can be either a specific RGB value, where the Red, Green and Blue components are each expressed as two hexadecimal numbers:

color="#CE0F3E"

Or, 

any of the predefined color names: 

color="red"

The supported color names are listed below along with their corresponding RGB value: