Glowing Firmament
Glowing Firmament (#02D9D3) is a true cyan with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (178°, 98%, 43%) places it in the highly saturated band at a mid 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
The progressive participle of glow, to emit light — used as a color word since the medieval period for hues that read as if they were luminous from within. Glowing amber, glowing rose: the implication is moderate saturation combined with the optical impression of internal light. Sits in the bright-bucket alongside radiant.
The biblical sky-vault — and God called the firmament Heaven (Genesis). Firmament in literary and religious color vocabulary refers to the saturated deep blue of the cloudless midday sky as seen from a desert or mountain: a saturated, slightly cool deep blue with the optical brightness of a clear high-altitude atmosphere.
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.