MDX Cell Properties - FORE_COLOR and BACK_COLOR Contents
Applies to: 
SQL Server Analysis Services 
Azure Analysis Services
Fabric/Power BI Premium
The FORE_COLOR and BACK_COLOR cell properties store color information for the text and the background of a cell, respectively, in the Microsoft Windows operating system red-green-blue (RGB) format.
The valid range for an ordinary RGB color is zero (0) to 16,777,215 (&H00FFFFFF). The high byte of a number in this range always equals 0; the lower 3 bytes, from least to most significant byte, determine the amount of red, green, and blue, respectively. The red, green, and blue components are each represented by a number between 0 and 255 (&HFF).