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Peaceful Gloam Lagoon

#21c3dd
Notes

Peaceful Gloam Lagoon (#21C3DD) 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 (188°, 74%, 50%) 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
#21c3dd
RGB
rgb(33, 195, 221)
HSL
hsl(188, 74%, 50%)
HWB
hwb(188 13% 13%)
OKLCH
oklch(75.2% 0.126 212.2)
P3
color(display-p3 0.3646 0.7536 0.8533)
HSV
hsv(188, 85%, 87%)
LAB
lab(72.61% -29.84 -24.05)
LCH
lch(72.61% 38.33 218.87)
CMYK
cmyk(85%, 12%, 0%, 13%)

Etymology

Peaceful
adjective

Latin pāx, peace — adjectival suffix -ful. As a color modifier, peaceful implies a clear-and-restful-and-calm quality where the hue carries the visual register of Quaker-meeting-house still-and-meditative interior atmosphere. Sits at the crisp-and-calm end of the grid, parallel to serene and placid in usage.

Gloam
modifier

Old English glōm, twilight-or-dusk. As a color modifier, gloam implies a twilight-and-half-light-and-fading quality, the visual register of Scottish-Border-and-Hebridean-gloam hand-twilight-and-half-light-and-fading Scottish-Border-and-Hebridean-and-Orkney gloamed-and-twilight-and-fading surfaces under Scottish-Border-and-Hebridean-and-Orkney long-northern-twilight-and-blue-hour gloaming-and-twilight light. Sits at the modifier-and-mood end of the grid, parallel to dusk and shade in usage.

Lagoon
noun

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.

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.

#21c3dd
Original
#afbcdf
Protanopia
#97abdd
Deuteranopia
#00cdcb
Tritanopia
#a2a2a2
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
2.12:1
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
9.91:1

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
##21C3DD
Display P3
Display P3
color(display-p3 0.3646 0.7536 0.8533)
P3 has subtle headroomOKLCH chroma 0.126

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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