Hadean Daidai
Hadean Daidai (#7A210C) is a deep red with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (11°, 82%, 26%) places it in the highly saturated band at a dark lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. For a confident two-color system, pair it with its complementary cyan. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Greek Hadean, of Hades — adjectival form of Hades. As a color modifier, hadean implies the deep cool-darkness of the classical-Greek underworld realms, with literary-poetic register. Sits at the deep-and-cool end of the grid, parallel to plutonian and Stygian in classical-mythological register.
Citrus aurantium, the bitter orange — daidai in Japanese, where the word also means for generations because the fruit hangs on the tree across multiple seasons. Used in New Year's kagami-mochi offerings and as the etymology of daidai-iro, the standard Japanese word for orange. The color refers to a fully ripe daidai on the branch: a saturated, slightly red orange with the matte finish of citrus rind. Brighter than tangerine.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.