Penumbra is a mathematically balanced color scheme designed in a perceptually uniform color space, with base colors inspired by the natural interplay of sunlight and sky. It separates luminance, chroma, and hue to make the most efficient use of the available color space on standard electronic displays. The palette consists of nine nearly symmetric base colors, which are used to build the main light and dark themes, along with two additional high-contrast dark variants tailored for people...