Symbol Styler

The Symbol Styler tool lets you apply or remove a graphic style from a symbol instance. You can control the amount and location of the application. For example, you can apply a style gradually so that some symbol instances display the style at full strength and others display the style at partial strength.

SOURCE:
https://helpx.adobe.com/illustrator/using/symbolism-tools-symbol-sets.html

RGB Colors - Additive Colors

RGB colors are called additive colors because you create white by adding R, G, and B together—that is, all light is reflected back to the eye. Additive colors are used for lighting, television, and computer monitors. Your monitor, for example, creates color by emitting light through red, green, and blue phosphors.

SOURCE:
https://helpx.adobe.com/illustrator/using/color.html