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Disciplined Lagoon

#21b8d9
Notes

Disciplined Lagoon (#21B8D9) 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 (191°, 74%, 49%) 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
#21b8d9
RGB
rgb(33, 184, 217)
HSL
hsl(191, 74%, 49%)
HWB
hwb(191 13% 15%)
OKLCH
oklch(72.4% 0.124 217.7)
HSV
hsv(191, 85%, 85%)
LAB
lab(69.19% -25.69 -27.10)
LCH
lch(69.19% 37.34 226.54)
CMYK
cmyk(85%, 15%, 0%, 15%)

Etymology

Disciplined
adjective

Latin disciplīna, teaching / training — past-participle of discipline. As a color modifier, disciplined implies a clear-and-controlled-and-careful quality where the hue carries the visual register of careful-edited-and-restrained design-decision. Sits at the crisp-and-orderly end of the grid, parallel to methodical and orderly 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

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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.

#21b8d9
Original
#a3b2db
Protanopia
#8ba2d9
Deuteranopia
#00c3c2
Tritanopia
#9a9a9a
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
2.35:1
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
8.92:1

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