noun
direct color specification
Computing term for specifying a color directly, e.g., by RGB values or hex code, rather than using a palette or named color.
CSSでは、直接色指定に16進数を使うことが多い。
In CSS, hexadecimal numbers are often used for direct color specification.
Compound of 直接 (direct) + 色 (color) + 指定 (specification). A technical term likely coined in computing contexts.