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Steady Age Lagoon

#21b4df
Notes

Steady Age Lagoon (#21B4DF) 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 (194°, 75%, 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
#21b4df
RGB
rgb(33, 180, 223)
HSL
hsl(194, 75%, 50%)
HWB
hwb(194 13% 13%)
OKLCH
oklch(71.7% 0.129 224.1)
P3
color(display-p3 0.3381 0.6956 0.8571)
HSV
hsv(194, 85%, 87%)
LAB
lab(68.23% -21.65 -31.86)
LCH
lch(68.23% 38.53 235.80)
CMYK
cmyk(85%, 19%, 0%, 13%)

Etymology

Steady
adjective

Old English stede, place, position — drifted to mean firm and unmoving. Used as a color modifier since the seventeenth century for hues that read as reliable rather than dramatic. Steady gray, steady green: moderate saturation combined with optical calmness. Sits in the crisp-bucket center alongside settled.

Age
modifier

Old French aage, period-of-life. As a color modifier, age implies a long-passage-of-time quality, the visual register of Bronze-and-Iron-and-Stone-Age multi-millennia archaeological-period age-and-epoch-marked surfaces under multi-millennia age-and-epoch-defining time-deep light. Sits at the modifier-and-time end of the grid, parallel to era and eld 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.

#21b4df
Original
#9cb0e1
Protanopia
#849fdf
Deuteranopia
#00c1c2
Tritanopia
#989898
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
2.43:1
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
8.66:1

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
##21B4DF
Display P3
Display P3
color(display-p3 0.3381 0.6956 0.8571)
P3 has subtle headroomOKLCH chroma 0.129

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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