Brilliant Mizu
Brilliant Mizu (#21D9E9) 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 (185°, 82%, 52%) 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
From the Italian brillante, sparkling — used as a color modifier since the seventeenth century for hues that read as optically active beyond their literal saturation. Brilliant green, brilliant blue: the implication is luminance combined with the slight sparkle of a high-refractive surface. Sits at the bright-bucket center alongside vivid and bright.
The Japanese word for water — used as a color word for the saturated pale blue of fresh spring water and the mizu-iro of traditional kimono linings. Mizu spans the cyan-blue boundary in Japanese color vocabulary. The color refers to fresh spring water in a Kyoto stone basin: a soft, slightly cool pale blue with the optical clarity of cold mineral water.
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.
Wide gamut
The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.
Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.