Represents the "C" entry of the outline item dictionary object.

It is an optional entry defined as part of the PDF 1.4 specification.

It contains an array which contains doubles, representing PDF numeric objects.

Items in this array should have a minimum value of 0 and a maximum of 1.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 153, page 369.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 151, page 443.

The colour is expressed as an array of three RGB components each in the range zero to one. Black is the default when this entry is absent.