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Inviting Aqua

#21b0b5
Notes

Inviting Aqua (#21B0B5) 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 (182°, 69%, 42%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. 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.

HEX
#21b0b5
RGB
rgb(33, 176, 181)
HSL
hsl(182, 69%, 42%)
HWB
hwb(182 13% 29%)
OKLCH
oklch(69.0% 0.112 198.7)
P3
color(display-p3 0.3311 0.6802 0.7031)
HSV
hsv(182, 82%, 71%)
LAB
lab(65.52% -33.22 -12.83)
LCH
lch(65.52% 35.61 201.12)
CMYK
cmyk(82%, 3%, 0%, 29%)

Etymology

Inviting
adjective

Latin invītāre, to invite — present-participle of invite. As a color modifier, inviting implies a clear-and-cordial-and-encouraging quality where the hue carries the visual register of warm-inviting-and-encouraging entrance-foyer color tone. Sits at the crisp-and-cheerful end of the grid, parallel to welcoming and hospitable in usage.

Aqua
noun

Latin for water, borrowed into English as a color name in the early twentieth century — initially for the pale blue-green of swimming pools and tropical seas. The color refers to a clear-bottomed swimming pool in midday sun: a clean, slightly green-shifted light blue with the optical clarity of filtered water. Cooler than seafoam, lighter than turquoise, with the mid-century weight of a word that paints itself across postwar interior decor.

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 explore

Harmonies

Accessibility

Color-vision simulation

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.

#21b0b5
Original
#a3a7b6
Protanopia
#8f99b6
Deuteranopia
#00b7b1
Tritanopia
#929292
Achromatopsia
WCAG contrast

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.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon White
2.64:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
7.94:1

Wide gamut

Display P3 representation

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.

sRGB hex
sRGB hex
##21B0B5
Display P3
Display P3
color(display-p3 0.3311 0.6802 0.7031)
P3 has subtle headroomOKLCH chroma 0.112

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.

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