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Inviting Plasma Robin

#66d1cc
Notes

Inviting Plasma Robin (#66D1CC) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (177°, 54%, 61%) 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
#66d1cc
RGB
rgb(102, 209, 204)
HSL
hsl(177, 54%, 61%)
HWB
hwb(177 40% 18%)
OKLCH
oklch(79.6% 0.099 191.3)
P3
color(display-p3 0.5090 0.8100 0.7967)
HSV
hsv(177, 51%, 82%)
LAB
lab(77.75% -31.98 -6.98)
LCH
lch(77.75% 32.73 192.31)
CMYK
cmyk(51%, 0%, 2%, 18%)

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.

Plasma
modifier

Greek πλάσμα, something-molded-or-formed. As a color modifier, plasma implies an ionized-and-fourth-state-and-stellar-glow quality, the visual register of solar-corona-and-fluorescent-plasma hand-ionized-and-fourth-state-and-stellar-glow solar-corona-and-fluorescent-and-neon-tube plasma-and-ionized-and-fourth-state surfaces under solar-corona-and-fluorescent-and-neon-tube laboratory-and-stellar-and-aurora ionized-glow-light. Sits at the modifier-and-cosmic end of the grid, parallel to corona and nova in usage.

Robin
noun

The American robin (Turdus migratorius) — though the color refers not to the bird's red breast but to the egg, robin's-egg blue, a pale slightly green-shifted blue produced by biliverdin pigment in the eggshell. The color is the inside surface of a fresh robin's nest at peak laying: a soft, slightly green-shifted pale blue with the matte finish of avian eggshell. Lighter than aqua, cooler than turquoise.

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.

#66d1cc
Original
#c6c8cc
Protanopia
#b5bbcd
Deuteranopia
#19d6cf
Tritanopia
#bababa
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
1.82:1
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
11.56:1

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
##66D1CC
Display P3
Display P3
color(display-p3 0.5090 0.8100 0.7967)
P3 has subtle headroomOKLCH chroma 0.099

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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